Devil's dickvocate

A person who genuinely holds and argues objectionable opinions, usually on the internet, until the point where the thread doesn't go the way they expected; at which point they try to deflect the justified heat by claiming to be a 'devil's advocate'. A constant source of irritation to people who spent the energy arguing with them.

"Did that guy really just equate jokes about Easter to jokes about Muslims being terrorists?"
"Yep, but once he gets flamed he's gonna say he was only trying to start a debate; typical devil's dickvocate"

"You want a vegan option? What if I demanded a steak option in a vegan restaurant?"
"Stop being a devil's dickvocate Miles"