I would see a big red flag on the person if they would start discussing religion even at non-work settings, unless I know that person really well. (And if the person knows me very well, I don't think they will bother...)

Someone having religious beliefs does not give them right to rude with their colleagues, while his desire to hold certain religious beliefs respected and accommodated where appropriate (which would be discrimination if not) that does not mean people around him need to respect what he believe.

From my past encounters with religious people, I can't help notice there's mix up on this.