>Otherwise, people being horrible really isn't your problem unless you train yourself to be very conscious of their opinions and to care deeply about them.
I don't buy this. If an internet forum like FaceBook, Twitter, Reddit, or whatever allows increasingly toxic behavior it eventually spills into the real world. For example, unmoderated forums facilitate doxing and incitement. What happens when an online harasser posts someone's home address, work address, and childrens' schools online with a call to real world violence? Should the victim just not care? What if online trolls set about smearing your professional or personal reputation? What if they decide to out you as gay to your parents or in a country where being gay is illegal?
And don't tell me you can simply avoid going online, that isn't practical. Its precisely places like Facebook, Reddit, Twitter, etc where marginalized people can find a supportive community. Also the internet should be for everyone, not just the most horrible, hard, and callous among us.