I understand that what's draining you is the repetitiveness of having to reprimand players continually. And this it seems has almost "broke" you and what seems to be your patient nature.
Understand that it is often easy to generalize a group of players such as "Melee DPS" like they are repeatedly doing wrong(almost like they are a single entity), where in fact, you are coming across different individuals time and again that are doing wrong. Think of a teacher in a class, many times they've seen pupils do wrong, year after year. Would that teacher just kick pupils out of the class for not understanding something? A good teacher wouldn't that's for sure! A lot of individuals play this game and many play it well. Everyone's a teacher to some degree or another. Humans are wired to problem solve, when something is wrong we notice it above all else. It's why you see many forums that seem overly negative because most of the time people go to a forum when something is wrong and they want to fix it. Meanwhile, people that are without problems are playing away contently.
Anyway my point is that kicking is the easy way to solve a problem, but don't give in to that slippery slope which can end up changing yourself for the worse and possibly even the person you kicked! They might learn something, but it likely won't be what you wanted them to learn.