SE is the one that makes the rules. If its against the rules to be rude or toxic and you still do it, its your own fault and not SEs. We could discuss if some rules are a bit harsh and maybe if some of the punishment for minor things should be taken away after a certain time of being well behaved but everything else makes sense. This is a online game which means that a huge amount of different people play it. You will always have those in it that are just jerks. And those will be punished with that so that other people can play mostly in peace. Of course you will always have those horrible ones that still manage to play the game and you might have the few cases of people that are well mannered ones but just lost their cool in an argument..but for that you have warnings and short bans. If you got your account completely banned you are either doing something again and again (which seems to be the OPs case) or you have done something really bad like pure cheating on the game.
People have a hard time believing the full story of the OP because its only one sided and because for most of the time the GMS do judge fair and dont just hand out bans like that so often. So it does create the feeling that maybe the behavior is worse than its written. Also just because they see it as unfair does not mean that others have to see it that way too and wanting to change rules just because they cant controll their emotions is just bad imo.
Mental illness should not be used to push SE into a certain position. Its on each of us to judge if we can savely play a multiplayer game within the rules of the game. And if someone cant then either they have to stop or change. Of course changing is not easy but why should SE do something? Where would it stop? How bad would this be for the community if rude people are not fearing perma bans anymore?
And I am sorry but 216 hours of ban sounds like something way more than minor. And if you did some huge rule breaking then its your own fault.