Can't say that's too common anymore.
But people of any belief system Are welcome on the site (per the site owner) long as they aren't promoting other beliefs.
I actually find most troublemakers claim to be Christians, many have been here for a while.
On certain topics, I think certain people get "triggered", for want of a better word.
I've seen otherwise sensible Christians (of the heliocentric theory persuasion) get quite animated and personal when debating the shape of the Earth. I don't think it's really that they're troublemakers, it's just that (unknowingly perhaps) certain non-essential beliefs are so treasured for them, these beliefs become the "hill for them to die on".