I do wish though you could leave games without getting punished some times. At the same time i realise why you cant but when you have most of the team raging at you, and even more so when you know they are way off, i'd quite happily lose the LP and forfeit the game as id rather just play another but obviously you get the time bans etc.
I'm kind of torn in games like that though because you get dogs abuse but then they expect you to help them in TF's and stuff.
Try setting team and opponents to ignore on chat. I think the commands on the first post or google it. You're still get the pings but no chat I think you will find it will improve your experience. You may want to post a message to everyone just advising at the start chat is off

Be interested if that works, pretty sure it will