The difference is in the context of the moment. With mortality in question, most often, an anti-religious person will not bring up the subject, unsolicited. Conversely, the religious see this moment as "their moment" to bring up their brand.
The thing to keep in mind in these situations is that the religious person means well.
That's because atheist don't believe in an afterlife or a grand plan God has. So why would they comment about things they don't care about as it is a moot point? With religion, the afterlife is one of the salient features of their beliefs. That no matter how unfair, unjust, and cruel life is, that there is the ultimate cosmic justice in the afterlife. This can bring solace and meaning not only to death but to life itself.
Sure Wes didn't ask for any religious support or advice. He hasn't asked for any support and advice. People give it because they care. If Wes doesn't appreciate it you can be sure he will speak his mind. I'm surprised that he hasn't told Marty to just shut up already with all this kale, cabbage, grass-eating bullshit. That's the guy that should be attacked as I, and a precious few have done. And to make matters worse, not only is he giving just nonsense advice, he's trying to portray Wes as an idiot for not following his advice that only turned Marty, himself, into a big, fat, autistic, blob.
But he's given a pass but not people of faith.