I'll argue on having to listen to them. I'm all for free-speech, no matter how vile it is. I'm also all for self-controlled censorship, and tools to facilitate that. If you don't want to hear, say, racist bullshit, ignore it, and move on. If it becomes too noisy, create a filter, and move on. If it is still too noisy, it's probably a good sign that your not fitting in well with the community.
1. We don't always want to express all our opinions and thoughts among people we know, because they carries significant social cost. So we end up saying a disproportionate amount of those things anonymously online.
2. It used to be that nobody had to listen to the outcasts and the lonely. People we don't enjoy being around. But now they can participate in online forums as much as anyone.
In part, it's a good thing that these voices can be heard, and that they can find likeminded to talk to. But a lot of them are outcasts because they're jerks, and online we do have to listen to them.