Swiss chees model of ~~accident~~ tyranny prevention
Governments are imperfect systems, you wanna have redundancies over redundancies. What you are saying is kinda like "I don't think we need separation of power, we just need to get the laws just right so noone can break their election promises and abuse their power".
As cheese layers go, not having a way of permanently stripping people of rights, and stripping prisoners of as few rights as possible temporarily, is a pretry solid cheese layer. In governments, it's relatively easy to introduce laws targeting critical systems of balance like protesting, because governments have to change laws as one of their main functions. Separation of power is nice, it limits bad (vague) laws, and allows implementing tiers of importance in laws like constitutional laws being harder to override than regular laws, among many other benefits. But if protesting is allowed in the cpnstitution, criminalize making noise yaknow.