It's only words and more times than not one can feel the intent, which at the end of the day it's much more important. It's not what we say, it's how it is said......

When I’m lost my dad a year ago, it was infuriating to hear that from my coworkers. I had to walk away from conversations several times because I was so upset. I think it’s rude to just assume that someone believes in an afterlife

I realize they didn't know us very well, and they mean well. I just say "thank you" and move on. I saw no point in causing a stink about it. I was comiserating with a close friend when some Christians tried to tell him our friend was in a better place and he went off on them. i saw this was coming and I tried to intervene. They looked like a kicked puppy when he was done.

It's hard for anyone to know what to say when someone dies. I'd cut them some slack (unless they're generally aggressive pricks).

I ask them, if they actually think that being dead is being in a fucking better place? Now, people usually avoid me at funerals.

I am a bit strange as I don't miss people - I enjoy friendships in the moment but I have moved around a lot in my life and have left many people. The idea of death doesn't worry me at all given how rotten my society seems ot have become I would welcome it in the door-

My family were all mentally unstable and I havent seen my brother for years don't know if hes dead or alive and its not that important anyway - I think I am pretty self sufficient and probably not as crazy as my rellies who are pretty much all dead now anyway

They mean well - I just leave it at that.

I would kick the shit out of them if they know I am an Atheist mourning my Atheist love....shove their evil belief up their empty asses

It doesnt bother me, though it is tempting not to say "where is that? The ground? Up in smoke ?" or "with the way the world is now, the ground is starting to look pretty good!"
My grandmother she was a hilarious atheist, as her parents had raised her to be. My nan had a saying "you'd f up a church!" (Meaning your so terrible you would f up something already completely f uped!) Though she would use the actual f word, I won't type the full word here, but you get the point. When she died a few years ago, an uncle of mine decided to make a huge religious spectacle of it, even while knowing she was against religion and openly atheist. See my dearly departed grandmothers son, my uncle, married into a Pentecostal family and became the super religious zealot, self righteous person that she tried to raise him not to be. He had it in his head that she needed to be saved and if she wouldnt let him do it in life, he'd do it in her death. He had his brother in law that is pastor of some mega church in phoenix fly in on his private jet to do the funeral...now I know she would of found humor in having had this huge religious funeral with all the trimmings! So the rest of the family being the jovial atheists she taught us to be had viewed it as a joke and carry on the legacy of finding humor in most things. In some way she lives on in the way we keep that humor going. We couldnt be upset about it. Not when she would of found it hilarious.

I myself hate that statement only because when I lost my husband that was the last thing I wanted to hear. People mean well but it just aggravates the hell out of you.

Fortunately I haven't been confronted with this nonsense but being the mostly polite chap that I am my response would be along the lines of 'If it makes you feel better then think it, but don't assume you speak for me'

It would annoy me a little, but I would just smile and nod, recognizing that it was meant in a way of comfort. If they persist, (and if applicable) I would say, "they're not suffering any more". It's a half agreement, but seems to be acceptable.
I don't typically challenge someone (or their beliefs) who is genuinely trying to be supportive.

I just ignore them because of their ignorance

I roll my eyes but only in my mind. Kind words are always appreciated. And I don’t totally disagree. Just that my idea of better place is non existence or recycled into the universe or whatever. I don’t feel the need to mention thst, either, though. Others need to believe in heaven to deal with loss. Who am I to take that from them?

It happend to me after the death of my wife, and it made me furious. Other platitudes that I find offensive are "I will pray for you" or "God will not give you a burden greater than you can bear"

Premise rejected.