Can we PLEASE have a chat modifier toggleable by ourselves?

I've been chat banned twice and now am on the bad end of a two week suspension. "Just change your behaviour" people will tell me, and yes I have tried. I just can't seem to remain calm when things go wrong, case in point the game I was banned for (which yes I understand is the straw that broke the camels back) was a 0lp second loss caused by ADC/Support going 0/5 then declaring mid/jungle as "shit" and going afk in fountain. I got a bit upset and ranted some at them and that got my the boot. I don't at all think I am undeserving of this ban, I am happy to serve my time. However, I would love to have the option to "chat restrict" myself, just a toggle that turns off my ability to speak in game, would be ever so helpful in stopping this happening to me in the future. I have previously asked about this and been told me, but no harm in asking again, or asking for clarification as to why this isn't possible.
Report as:
Offensive Spam Harassment Incorrect Board