If an atheist says "Fuck God" or "God is a douche" then the Christian becomes offended and annoyed by these words.
I know many Christians who accuse atheists of being angry. And maybe some are.
But what I find funny, not to mention rather telling, is that Christians think it's perfectly alright to say "I'll be praying for you..." in condescending fashion when they find out one of their friends or family members is an atheist not realizing it's about as annoying as a rude atheist saying "Fuck God, that asshole."
Sure, a Christian might say, but hey, I'm genuinely concerned for you. For your soul. And that this comes from a good place, rather than just being a rude person calling someone's sacred idol or preferred deity names.
And although their heart is in the right place, it's no less rude or condescending to assume someone is in some way not good enough to reach whatever made up standard you're holding them to, religious or otherwise.
Whereas calling a non-existent entity a nasty name really doesn't harm that entity any -- because it doesn't exist.
The moral of the story is... it's not about you. It's about how you treat others.
Me calling Superman a "Big pussy" doesn't hurt you any. You judging me as less than and thinking I need fixing makes it about me and in a way that's designed to make me feel less of a person... so yeah, you're praying for me? Don't.