When is a Religious Belief Delusional?

[CapnAwesome]

Meh, fuck em, a compulsion to use softer language is just another example of undue deference to a tradition that has been browbeating the shit out of people (and worse) since it's inception.

I suppose I could coddle believers, like fragile children...but I'm not sure that's an instance of showing respect.

I'm not being deferential by not calling someone delusional, I'm just being precise with my language. I believe words have meaning, beyond some dictionary definition, which normally are so broad that it's not really how a word is used in real life.
In real life, if I say someone is delusional, I mean they are mentally I'll. Since I (and pychologists) generally don't think Theism is the same as mental illness, I don't use the term. 
I'm highly skeptical that people who call Theists delusional online call their theistic family or friends or co-workers delusional in real life. So it mostly seems to be a phrase just for pissing people off online. 
That being said, these people are delusional: