To be honest, this person getting banned isn't as big a problem as not having a feature that permanently lets you NEVER be matched with people EVER again.
The "unskilled player" report apparently does this in some form, but generally if I never want to play with a player again, they're getting reported for something else entirely, because they're either deliberately feeding/afking/so rude they should never play the game.
I hate getting matched up with people that I recognize as ones that do the above and having the odious choice of dodging the game or playing with someone that I know is absolutely toxic, when I should never have that choice in the first place, because they should never be on my team 