There's dickheads everywhere, you can't necessarily remove them from the internet. As long as people are under the presumption that they're 100% safe behind a keyboard, they'll continue to be keyboard warriors.
People don't troll for "lulz" or to make others mad, they do it because their own lives suck, it's that simple.
As for people intentionally wiping a raid. I'd like to know what mechanics could be abused to wipe a LFR encounter. 3/4 the raid can be dead and your LFR encounter can still be easily beaten before an enrage timer, it's a ridiculously watered down version of even a normal raid.
The ONLY type of real trolling I've seen recently came on Stone Guards on an alt.
Two tanks from a guild "Encore" on Illidan were trolling on Stone Guards and kept stoning the raid to reset the bosses. They thought this was absolutely hilarious each time too and they couldn't be kicked because everyone said they encountered a "4 hour wait timer".
Mind you, Encore used to be a World 50 Top Guild but apparently they take anyone who wants in now days since they're no longer anywhere near the top of who they used to be. It's sad man, this community absolutely disgusts me.
All everyone cares about is epics because Blizzard has created this sense of entitlement rather than a sense of reward and appreciation. I sincerely hope they require characters to have 10/10 Gold to even use the queue system for LFR. Will this kill off all the trolls? No, nothing will. Put everyone's face/name and address in the "Inspect" player window, let's see how many trolls there are then and how many "Keyboard Warriors" there are then. That would be dangerous for innocent players as well though so that won't happen.
However, requiring people to complete Gold Proving Grounds to prove that they have the intelligence level above a Goldfish would be a great start though. Also: DPS tests to make sure they're doing at least 50% of the optimal DPS they should be doing at their ilvl would be a great start too... not that I don't thoroughly enjoy long ass runs because the majority of the bad dps are just sitting there doing 30-50k dps (somehow...).
It's just like the dickwads who did 5-9k dps in Cata LFR who seemed to win a lot of the items.