What I don't understand about chat bans/suspensions

What I fail to understand is, is there any rhyme or reason behind these chat bans or suspensions? What determines someone gets one over someone else? Is it based off how bad the content is they are spewing out? Or is it just based off volume of reports?

I've been chat banned before, and I've been suspended before. I'll admit im "toxic" (something I don't agree should be enforced so heavily but that's another topic) but aren't there varying degrees? When someone just blows up and for 40 mins just starts yelling "!@#%!@$%!@#$%@#!%$@#%@#$#@!$^&$#%&%!%@#$!@#^@#$&" the entire game, absolutely they deserve a chat ban or suspension. But is there a difference between him and the guy that goes "omg stop killing yourself, you keep acting like a complete idiot" ?

I just got out of a game where a party in dynamic que harassed me, THE ENTIRE GAME, and in lobby, and sent me friend requests to probably keep harassing. I NEVER did anything like that, but I still have gotten punishments. Are these people just lucky? Did they scoot by unnoticed somehow? Or is it all just random?