What's the point of being obnoxiously religious?

I believe in live and let live. As a matter of fact, I couldn’t imagine living anywhere that didn’t positively seethe with multiple ideologies, nationalities, sexual identities and races. I’ll happily argue theory with you all day and then argue for your right to hold apposing views.

But I don’t understand the point of pushing people away.

We’ve all experienced it – those people who answer everything with a religious reference, who aggressively push their own views, who denigrate anyone who disagrees. Is this some bizarre, misguided attempt to convert people (by alienating them?!?) or are they just proving to the world how pious they are?