It’s a matter of when and where.

A protest isn’t inherently able to be made anywhere any time. Public property is shared property, so in order for one group to use that to the exclusion of others takes planning. On private property, nobody is obligated to allow you there at all, and not all universities are public.

The street you block in protest isn’t your street, it’s our street, so you have no more or less rights to it than I do. A permit, in theory, is just a fancy way to make sure that anyone else that would be using that place can have alternatives. Traffic being rerouted, etc.

There are also health and safety issues like overloading bleachers being a risk, or a space not being able to be evacuated in an emergency because of too many people.

You’re right, if permits are not granted equally, it’s a huge problem, and abuses can occur. They do occur. But as long as the entity (be it a government or a university or business) isn’t placing undue obstacles, grants permits equally, and everything is done without corruption (bribes or such), that’s how the most basic peaceful protest has to work.

This isn’t saying that there can’t be other forms of protest. There are many forms available. But a simple awareness protest? It needs to be peaceful, cooperative, and only marginally inconvenient. Remember, that kind of protest is about awareness, of making sure people know and possibly gaining support. It’s a flies with honey vs vinegar.

Now, illegal protests, disruptive protests, and even violent protests have their place too. As do rallies, which can be seen as a type of protest, but isn’t really the same imo. But you have to choose when and where to apply those tools effectively. Some protests, the entire point is to cause disruption, get arrested, and use that as a tool to achieve a goal. But a cooperative legal protest can do things that type can’t.

Remember, the right to free speech does not guarantee you can exercise it everywhere. Your right to free speech ends at your neighbor’s door, so to speak. You can say what you like, but she doesn’t have to let you say it on her porch. You can be asked to leave, and should you refuse, be removed after some hoop jumping along the way (which varies by state and municipality).

A public space like a street is the same basic thing. You have a right to use it, and so does everyone else. Your freedom and their freedom may come into conflict. Having some kind of system for resolving that issue is necessary. Permits work for parades, parties, and protests.

Even with the kind of anarchy that most people identifying as anarchists espouse, there’s a social contract involved in that kind of thing. It’s only a matter of the mechanism involved.

Besides, there’s always been limits on speech. Collectively, there’s an understanding that there are limits where, when, and how they can be expressed. The whole “fire in a theater” trope is an example. There’s “fighting words” laws on the books. The only question is what any given social structure has decided those limits are.

Generally, whether it works correctly or not, representative democracy promises that the limits are agreed on via those we elect to do so. That has flaws of course, but that’s the US on a simplistic level. We’ve all agreed to the limits in one way or another, or can choose to try and change those limits (or the social structure itself).

But if that slippery slope slides too far, well, that’s when protests become revolution, in theory. Assuming enough people agree and work together. It doesn’t seem to happen very often, but that’s the ultimate safeguard against a democracy failing.