Ignoring them is generally the best course. 2 friends and I were queued for a WP a couple nights ago and got a tank in Darklight that ran right off the bat without Protect or Adlo or anything, nor said a word in chat. He grabbed everything up to the room with the Vultures and Tonberry, popped Hallowed Ground and promptly died after and began to rant and rave about how terrible we all were before threatening to AFK until we gave him what he wanted. He eventually became bored of singing to himself when he wasn't getting any response and left on his own.

It's pretty much the same reaction you give to real life jerks.