Just to add to this, playing without talking yourself is fine, I suspect most players do this. If you need to block everyone in the lobby except the folks on your ship that is a-okay too.
You can crew in silence pretty adequately, and you can pilot with the 'V' menu (accessed by pressing the 'V' key), and the 'B' targeting reticle which highlights what you want to target.
Having the sound settings configured so the pilot is inaudible is considered extremely rude. This is a highly co-op focused game, and if someone cant hear what the pilot is saying it cripples the team. Think playing an FPS after unplugging the mouse. That said if you don't want a conversation that's not going to be a problem for most pilots, just accept load-outs and follow orders and you will be fine.
Just to add to what Solidus said, the reason you need to unblock folks afterwards is that the matchmaker tries not to put you on a team with people you have blocked. If you leave everyone blocked you'll run out of folks to play with.