I think of these questions all day every day and we have our own moderation channel in Slack where we debate them, sometimes with a lot of passion. We all bring our own biases and sense of morality to the debates.
We view ourselves as publishers of user-generated content. We're different from someone like The New York Times because we don't hire journalists and we don't edit what our users post. But we do have to make judgements on what is hate speech, bullying, dangerous, etc., and there will be furious debates when people disagree.
The Internet has an incredible variety of sites that let you say almost anything. Those are easy to build. It's much harder to build a service that's all about great public conversations, but that is our mission.
We will soon enable panel conversations, which I don't think have ever been done on the Internet, except in video form. The thing is, the Internet is the only venue on earth where there is an expectation that anyone can join the conversation, but it's the worst place to have that expectation because it only takes one person to ruin it for everyone. In real life, the expectation is when you assemble a panel on a stage, it's in everyone's interest to let the panel speak without someone from the audience trying to interject.
It's in our interest and yours to find really interesting panelists that millions of people would want to hear from, but even then we will have to block some panels from seeing the light of day.