The ToS definitely does not say you can't offer advice or make requests of people. The ToS DOES say you can't harass people about it.

A couple of duty relevant ToS points:

You cannot force a gameplay style onto another player. Thus, either you leave the instance or you kick them.
You cannot harass other players.
You cannot engage in lethargic gameplay that gives an advantage to the opposition (other team, enemy mobs, etc).

The third point circles back to the first one - if someone's gameplay is dragging the rest of the team down, you can politely request them to up their game. This then circles down to the second point - If they refuse or become hostile, you can kick them, just as you are not allowed to harass people over gameplay, they are not allowed to harass/act like jerks in response to polite requests. Therefore, if they are refusing or acting hostile, there's the kick button.