I think it's a vicious cycle. If you harshly punish people for saying certain things, you create taboos. That causes people to avoid discussing these taboo topi

I think it's a vicious cycle. If you harshly punish people for saying certain things, you create taboos. That causes people to avoid discussing these taboo topics. Everyone knows that they're bad things, but there's none of the debate where you can practice fleshing out exactly what your objections to those ideas are. Then when someone says those things, you have trouble articulating why they're bad, and then you fall back on the threat of social exclusion.