I suspect our interpretations of the word "prudish" would vary from person to person in a social media setting. Any time my reaction might be considered prudish, it would probably be because the nudity or sexuality was introduced under what I would consider very inappropriate circumstances. For example: "Hello, my name's Bob and here's a picture of my junk!" - while I do appreciate that such directness takes all the ambiguity out of the decision to delete and block him, and is a real time-saver for me, it probably narrows the field substantially for Bob. People who want to introduce nudity or sexuality probably have more success if they demonstrate enough consideration to get to know someone and choose their moments for nudity and sexuality with a modicum of sensitivity. Just a thought.

Family teaching, body-shaming, bullying.... the list goes on.

Since a child, I have been mocked and shamed for being "too skinny." As a child, I made fun of my body to beat bullies to it:

"If I stick out my tongue and turn sideways, I look like a zipper."

In 7th grade, when I entered science class, boys sang loudly:

"She's a carpenter's dream... flat as a board!"

"She's a pirate's dream... a sunken chest!"

That's when I developed good posture and dignity. Head high, ramrod straight, shoulders back, I icily ignored them.

With a classic ectomorph body type, I have a fast metabolism, narrow frame, small bones and and trouble gaining muscle and weight. Didn't learn this until I began weightlifting in my 20s.

"You have a stick figure," a man said when I refused a 2nd date. Mean words sting.

Finally, I like my slender body.

Photos:

1. Age 12 with my sister Beth, 7.

2. Age 25, taking a break while hiking in the Olympic Mountains.

3. Age 58, hiking Deception Creek, WA.

4. Age 66. New haircut.

My prudishness is a reaction to over sexualisation of people in society and an attempt to keep my private life private. Largely it’s pretence, but I generally don’t enjoy sexist jokes especially offensive ones.
I wouldn’t know about the latter, having no disgust but a respect for others’ differences, as long as i can have mine respected.

Mostly I think it's the way people are raised. If you are taught that bodies in their natural state are shameful from a young age it will stick with you.

Personally, I'm pretty much asexual these days so it's just an annoyance. Most bodies I don't find attractive at all especially the anorexic ones that come from Hollywood or clones of Hollywood.

In some circumstances, bodily integrity and common decency. Nudity and sexuality are not appropriate to all circumstances and there are instances where the breach of these types of boundaries result in victimization, usually of women but also men and children.

A more important question might pertain to the source of the desire to breach these types of boundaries.

Ascertaining this was one of the reasons I joined this site...

In many cases, victimization (or even a keen awareness of victimization) may lead to a discomfort with sexuality. This is normal and natural, however unfortunate.

I've tried to understand this problem (and the source of it) most of my life. But luckily, I've lived in other countries enough to see that it's mostly cultural. And of course, religions usually paint a backdrop for much of the cultural bias. My most favorite place to be is Europe. I enjoy the relatively open attitudes about sex and nudity. I'm always pleasantly surprised to see nudity in movies and on TV. When I come back to the U.S. after a prolonged stay in Europe, I"m always shocked at the degree of sexual repression in our country.

The source is still religion.

Since attitudes to nudity vary so much, it is clearly a cultural phenomena, not one which is hard wired. It is also clear that it really begins only with the onset of civilization, since most of the societies that are completely accepting of nudity are hunter gatherer societies living in extended families or small tribes. In such groups there is probably a natural meritocracy, in that it does not mater much that grandfather is ugly, if he is kind strong and wise, he will be loved and honoured anyway. With the agricultural revolution population explodes however, and society therefore becomes bigger and values shallow, obvious in short term qualities more, including appearance. People in such societies will therefore almost certainly dress up to impress and maintain status.

If that is true, then we would expect to see that the more meritocratic a society, and the more local democracy it possesses, the more accepting of nudity it would be. And anecdotal that seems to be the case. The ancient Greeks for example, regarded their accepting attitude to nudity as a sign of their freedom, and the covering up of their neighbours, in the imperial states around them, as a sign of repression and a rigid stratified class based society. ( So this is not a new thought.) And still in the classical world, Rome started out as a society widely accepting of nudity, but became increasing one where covering up was the norm, as its democracy failed and it became increasingly imperial.

And when once the norm of dressing up is established, then those who do not do so are considered exceptional and attract notice, especially sexual attention if attractive, or revulsion if poor or ugly, and so it self perpetuates. Sadly for the political nudists, this probably means that any dream of creating a fair society by promoting nudity, is just that, a dream, since acceptance of nudity probably follows from being a fair meritocratic society, not the other way round.

Beats me!

It might have come out of the Enlightenment when righteousness turned into right-thinking, in other words, when it stopped being a matter for God and more a matter of social values.

Reaction formation. If they're not getting any, they don't want anyone else to. All wrapped in religious dogma that takes the pleasure out of sex.

Some people are just uptight about such things. Who knows where it comes from if not religion.Maybe discomfort wt the more primal side of being human?

One not getting enough of it themselves?

That is a really good question. China has been a predominantly atheist country since 1949 yet they still have The "Group Licentiousness" law.
The PRC Government still regulates sexuality to a greater degree than the governments of Western countries. Recently, Ma Xiaohai, a 53-year-old computer science professor,[17] was sentenced to 3 ​1⁄2 years in prison[17] for organising wife-swapping events,[18] breaking the "group licentiousness law" (聚众淫乱罪).

See link to source data

[en.wikipedia.org]

In a way-too-simplistic explanation: Patriarchal society's values are responsible. Patriarchal religion plays a big role in reinforcing mores, but that in no way means that only religious individuals are impacted.

In cultures with rigid separation of gender codes, where women are treated as potential property of men(hello Bible) and men are taught they had better cop a certain macho attitude and image and avoid ever appearing vulnerable, lest they lose their favored status, ...preditory behavior is encouraged and sexual insecurity increases.

Historically the least prudish societies tended to be pre-agricultural/hunter-gatherer cultures, in which wealth accumulation was not a social factor and collective sharing was a matter of group survival. Pastoral and agricultural societies allowed for wealth accumulation(notion of ownership and inequality) and led to subjugation of women. In such cultures, sexual insecurity and hence prudishness abounds.

Many people are embarrassed by their less than perfect body.

They all have their own reasons but for a couple of my friends it is lack of self confidence and a history of abuse. Myself, I just prefer the company of my own home. Or my partner's whenever I have one.

Hypocrisy, coupled with the need to exert control.

Religious ideas are so much a part of the western culture that it pervades everything.
Even the non-religious are affected by the religious attitude.
The idea of sin & unworthiness us deeply ingrained, culturally.
How many people complained about janet jackson's 'wardrobe malfunction' but don't give a damn about injustice? It's cultural heritage.
Women are taught to be ashamed of their bodies as a matter of control.
I agree with @nunya that most women have been abused; I've heard many stories from friends & lovers.
We must all strive to overcome all the shit that surrounds us.

Well, I think it's just the trauma of living. Many people are sexually abused as children, many are raped & if these things did not happen to them personally, they know at least a few that it did happen to. People you know & trust are found with child pornography, are accused by a friend of rape, or accused of sexual abuse by a child. People lie, people cheat, people physically abuse one another. It's difficult for me not to find human sexual behavior disgusting because of all of this.

One theory is that nakedness reminds us of our animal nature and mortality. We like to believe that we are different from other animals and are terrified of our mortality, hence the disgust.