AII AFK…

At what time were you playing and in which region?

Sometimes there are groups of users that run bots to level their accounts, usually this is done during times when there aren't a lot of players playing the game.
If you were playing at a time where there wouldn't be a lot of players playing (e.g. 3:00 AM), then that could explain why you encountered those.

I'm not sure if that is what you encountered, though I'd highly recommend not killing these kind of players.
Sometimes boosting services run these bots and try to get the player who bought the boosting server into that lobby. So killing those bots would look like that player having bought boosting services, which could get you banned.