You're making the mistake many people make in assuming all communication on the web is strictly two way, and that the only possible outcome of speech online is hurt feelings.

If I post your real name, address and bank account credentials online, or photos of you in the bathroom, or start a forum to plan acts of genocide against your race or religion, or maybe spread plausible slander about you on every social media platform I can, that's perfectly acceptable under your terms. But it doesn't help you if all you're allowed to do is set a filter flag on it. It's still there, having an effect.

The web isn't just teenage edgelords shitposting at each other for lulz anymore, there are actual real world consequences at play.