They can and do terminate accounts on a whim. The problem is that we allow them to do it. The community is eating itself from the inside. When a player is banned, the community in general approves. Exploiters ruin the game.
Exploiters are bad.
Therefore, banning exploiters are good. But exploiters are a part of the community. Sure, most of the time they are faceless peons who you maybe saw act like an ass in-game once. But on occasion, they are friends, guildmates, or even respected enemies. Believe it or not, I am in favor of banning some exploiters.