BM is part of the game, and making BM a bannable offense shouldn't even be considered.
EDIT:
Before you comment, do remember that the following is an in game loading screen tip:
"Competitive BSing is fine. Hate speech, not so much."
So I'm actually right when I'm saying the BM and competitive BS is 100% fine.
I've seen too many topics about "make saying EZ bannable" or "BM is toxic". I disagree
Honestly, BM is a part of any competitive fighting scene environment. In any other competitive game, fighting games and even real sports like boxing and MMA, BM and trashtalk is just a part of the game and is a strategy. It's not toxic to say "ez" after you kill someone. It's not toxic to type "?" in all chat after the enemy makes a mistake. Saying "nice ult" or "nice leash" isn't toxic. You might be tilting someone with it, but that's a strategy. I want them to get angry and keep on making mistakes. Winning is my goal, and I will use this strategy to accomplish that.
I won't insult anyone. I won't swear. I won't use slurs. I'll just BM a little.
Emotes have been added to be able to BM without needing to type, same thing. Someone dives me and dies? I tip my hat. They 4 man kill me but lose 2 inhibs? I dab on them. Someone misses his ult? I send them a thumbs up or a wp emote.
There is no difference between that and saying "ez", "nice try" or "worth me for 2 inhibs". One of the emotes is even called nice try.
"but you can turn off enemy emotes" You can turn off all chat. You can mute a specific enemy.
If you can't handle a little competativeness BM, you should mute a person or turn off all chat. Don't go crying for bans or reports when a person is only BM'ing.
Tl;dr
BM is not toxic, and you shouldn't ask for BM to be bannable. If you can't take it, mute someone or turn off all chat.