They are cracking down on it. Right before the season ended I got a 2 week ban. I was telling people to drink bleach and stuff so I wasn't too mad (or surprised). So I stopped doing that after my suspension ended. A day or two after it ended I got a 75 game chat restriction and 35 game ranked restriction. Ok whatever bro, I'll try and calm it down. A couple days later I got a 2 week suspension again. If I remember right the worst I did was tell a teammate that threw a 50 minute game getting caught that he should be in bronze 5. I thought it was fair, since that person just wasted 50 minutes of my time, but apparently not. At this point, I want to go back to telling people to drink bleach, because it sure as fuck didn't help when I stopped, so why bother.
The system doesn't ban you for one game. It does an analysis of your history games and looks for patterns of behavior. It's pretty clear that you have a history of toxic behavior. The system flags that. You are now "marked". If you keep getting reported, then it shows that the punishment isn't working and the system doles out harsher punishments.
You've received 2 two week bans in a relatively short period of time. A permaban probably isn't too far off in the future at that rate. Seems like you should probably take a long break from the game and get some perspective (and possibly some anger management). This is a game.