Theres a fix for OP's situation. Upon kicking a virulent player, the leader should wait 2min-4mins before hitting "find new members" that way, the troll will be put in another dungeon.

In the cases of OP, its usuallya tank or healer rejoining over and over again. Since both those roles tend to be in high demand, if you wait 2min-4mins before finding new members, theres a very good chance that troll will be placed with another group.

The solution is there, people just need to know about it, spread the word.