You really don't understand why that is? Or you do and just don't like it. I mean, it's not rocket science, eh?
Anyway, I used to wish this feature existed until chat mute was introduced, then individual team chat/overall chat mute functions. Might not be the smart bomb version of individual permamuting, but I don't mind a good carpet bomb mute personally.
Still would be nice to have for particularly deficient people to be silenced even if they're on your team without having to do it every time, but hell that just seems like asking too much at a certain point when I think about what the hell this is and how clicking a button is zero compared to real life and shit.