There is no reason to ban someone because they got upset and lashed out verbally.
NO ONE IS SAYING NOT TO PUNISH PEOPLE OVER SAYING THINGS, JUST TO NOT BAN THEM OVER GETTING MAD AND TYPING A SENTENCE OR 3 SO LONG AS THEY DIDN'T USE HATE SPEECH OR TELL SOMEONE TO HURT THEMSELVES.
If you use hate speech you should be perma banned. If you tell someone to hurt themselves irl you should be perma banned. If you tell someone "Stfu you bag of dicks!" however because you got upset at something they said or did you should get all chat and ally chat disabled for a certain amount of time. It should not let anyone know you are muted. It should not hurt your account or honor. Everyone loses their temper at some point weather in game or irl. Its not that big a deal. People are people because they have emotions and if we all where always in control of them human history wouldn't have any fighting or wars.
Disable their use of all and ally chat for a set period of time that they can look up in their settings where the option to turn them back is. Don't spam them with notifications after every game or inform them the mute is almost over. Just when it happens notify them they are being muted for a certain period of time, and that you're sorry they felt they needed to lash out, and you understand that sometimes the game can be frustrating, and that they can turn it back on after either a set number of games or certain amount of time. When it ends notify them the next time they login or finish a game and say you hope they have a pleasant time. That's it.
This will instantly help people calm down and think more rationally but it wont make them lose their account because they weren't perfect little robots. It will make it so hate speech is still punished but getting mad isn't gonna cost you potentially hundreds of dollars and years of time for the mere mistake of being human.