Because some people are natural followers and won’t do anything unless there is a nice safe herd doing it. In this case we actually need a herd to push back against authoritarianism. And if people don’t feel empowered until they feel safe then enough protestors must stand up to create that critical mass. It’s a painful irony: people won’t mobilize because no one has mobilized. What makes it worse is the mocking of the protestors for having the courage to go first.