Stigma. Thousands of years of it. To be without god is to be wicked and immoral in their eyes.

I've come across some rude/mean atheists. They make us look bad.

Ignorance.

Because we are not part of their belief (fear of foreign). Because we might threaten their faith (fear of doubt). Because many pastors preach that we are evil and dangerous.

We are not nice. Not to them. Nice is safe, we are a threat, they fear us fear engenders hate.

The same reason some atheists hate very nice people like believers

Not all atheist are nice. Some just pretend to be. I'm talking to atheist now and she say that she nice but her actions say something different.

Easier to demonize those who oppose your views then to accept them

Because we don't comply and fit in and deep down they know we could be right and make there whole life seam like the bullshit it is.

They be closed minded and uninformed about what an atheist is.

Take a look at the Trump Pinata group and that will answer your question.

Brainwashed by the churches. They are told not to mix with unbelievers.

It's conditioning. I remember my mother talking about atheists when I was little she would screw her face up and spit the word "atheist" out like it was a demon. I grew up thinking there was nothing worse. I know I'm not alone in being taught this way. I know atheists who are apologists for Christians because they think religious people should be treated better, because of their beliefs. I don't understand why we let them walk all over us. The first atheist I got to know was one of the most delightful people I ever knew. Unfortunately he died a few years ago. He changed what I believed about atheists. I never would have believed I would some day be one. Some of the nicest people I've ever known are secular people.

Because all atheists are NOT nice ,and some look down on ,and chastise believers thats why.

If they don't have knowledge of what it means, to be a non-believing person...they are simply fearful of the unknown! As a mtater of fact, most humans are fearful of the unknown of anything, to a more or lessor degree!

People hate whatever differs from their views

Lack of agency pertaining to ideas and beliefs, i.e. Ideas and beliefs are things that happen to me, not things I control; therefore, if I come into contact with an idea or belief that challenges mine, I have no control over what will happen."

Fear of being wrong

A lot of atheists are dicks! But also there is a lot of myths about us. For those of us that are in the position and have the personality, so be open and try to give atheist a different imagine. Im not taking about pandering ether! But we don't have to be dicks! Tone it down a little out there people.

Many see atheists as a threat to their delusions. No one likes being forced to confront the fact that they've been lied to all their lives. No one likes facing that they've believed lies.

They never look at the other aspects of my life and the things I do that are great in society. They only know I do not accept a belief in god.

I find that if I get to know someone first, then they find out that I am atheist there is usually not a problem. But if they find out that I am atheist first, they don't always try to get to know me. But those types of people are not worth knowing anyway.

People usually 'hate' on others because they imagining that that person has something that they themselves by rights should really have - (maybe self confidence/whatever ) because it can be very edgy being a believer. I am not always nice but I am always apologetic after a row.

Fear