When two people argue online in comments they both tend to come away thinking they were right and they defeated the other person.
I think you're right about people being silenced. I guess its a self-censorship for fear of hostility, if you speak out on either side of certain issues you'll have a bandwagon of ideological idiots who parrot a few key phrases they've learnt.
RE: Everyone is talking but no one is listening. Arguing online is pointless.