Well, some people try to sneak from start to obj and to delivery place and might not shoot at all. I dont think "shooting the enemy" is the priority of the game. Completing tasks to complete objective is what should be done. The bigger question is if you hindered or bothered your team with your playstyle that they were so unhappy. I rarely see lots of complaints over people who get 1-2 kills per map when they play some mortar or mg or flamer or covert op (sniper for example) that does no difference.
Warn, put to spec and explain would be better option. Direct kick is bit overkill, but that is just my personal opinion.