No one is trying to "silence" anyone.
Boycotting cannot "silence" anyone.
To actually silence someone you'd have to lock them up, or kill them.
While I don't agree with all of these people trying to take Rush Limbaugh off the air, and no doubt you'll make it seem like I do somehow this whole thing about silencing opposition is silly and stupid, that's not what's happening at all.
It's nothing but feel good rhetoric to make right wingers feel like they're engaged in a battle for their rights or something.