I brought this up to the top because A-Stock did indeed offer the best explanation ever.

When confronted with this seemingly disturbing photo from the Portland Tribune of a Bush supporter muzzling a young protester:

One might be tempted to think this is an assault on the 1st Amendment -- which it isn't as Jeremy pointed out in the comments as the Bush supporter isn't the government. One might also be tempted to think of this as battery of some sort.

But then the context emerges. This young protester was talking about Shaft, and the Bush supporter was merely urging her to "shut yo mouth." As Alex said, it's clear as DAY.