[AnkhMorporkian]

As a general concept I agree, but this is limited to your facebook friends. This isn't randomly joining a multiplayer server, this is intentionally adding friends to a space. Ostensibly, you should know them. Adding muting capabilities seems like some weird power play that'll just lead to bullying. If you don't want someone there, just remove them. Hell, unfriend them.

[joshuamorton]

And you've been able to mute people in various group voice chat programs (made for talking with friends) since forever.