This is Blizzard we are talking about, the kings of bad decision making
On the one hand, they want to make a genuinely fun game for both casual and competitive gamers
On the other hand, Blizzard should have known that putting casual and competitive gamers in the same room would create an environment more toxic than a vat of radioactive waste.

You know, I am not sure if I trust Big Brother Blizzard for this, I mean, there was a time that they banned a Torb main because he was playing Torb on a competitive team.

and heck, they even ban you if you spam emotes.
I think it's right to do something against people that call you trash and insults you for not killing 3 tank at full health as you're playing as Genji (or in any situation really), but at the maximum, you could just mute them and the only real way to say anything is through speedchat commands, not straight out banning them.
Banning would really for things like hacking/exploiting without reporting/scamming, etc.
( Also OP, put this to your source: https://kotaku.com/blizzard-is-now-monitoring-youtube-for-toxic-overwatch-1822465612 )