I don't understand the point in permanently banning players
All the toxic players can just create new accounts and be toxic in it.
All the toxic players can just create new accounts and be toxic in it.
They can, yes. Not all of them do though, so it's a net gain.
There is also the discouraging factor of losing all your unlocked content, which encourages another percentage to change their behavior.
Is it something that prevents a dedicated player from returning and being toxic? No. But it isn't pointless or ineffective -- just not 100% effective.
To say "your behavior is unwelcome here, stop coming back."
The making a new account thing is more an issue with league being free to play, the only way to curb them coming back would be to make league subscription based and that would just drive players to DOTA tbh.
So, what do you think they should do instead?