I could say the same to you, strike missions are for actually doing the strikes, if you're hanging back and killing pointless mooks that keep respawning infinitely anyway while other people are trying to do the actual mission as intended, you're not being a team player, save that stuff for patrol where it belongs and play the mission you're on while you're on it. As for trolls and leeches who intentionally hang back and let others do all the work, they get reported and forgotten about a few minutes later, as deserved, and I move on to the next match. Also it helps in that situation to go into a darkness zone by myself and commit suicide, it forces everyone to respawn on my location and stops the leeches from getting anything by screwing up their drop rate (which goes down after a hard wipe).