Loud is not the same as persuasive.
Chants on both sides. Megaphone feedback. Signs written to hurt rather than to explain. Phones held up, not to understand anything, but to catch the other side at its worst and post it.
Ask a few honest questions and the scene looks different.
Public protest can do real things. It can show how many people care, and it can put an issue in front of people who'd never have noticed. What it rarely does is change the mind of the person standing ten feet away. Nobody has ever been shouted into agreeing. What looks like persuasion is usually release: a lot of feeling with nowhere else to go.