Which also should be illegal, much in the same way employees on strike try to stop "line breakers" from going to work. That isn't just a protest, it's an illegal one.
I draw a clear line between a protest and physical interference. You may have a right to express your opinion but you don't have a right to prevent my passage.
This is why I have always felt that the First Amendment does not require cities to turn their streets over to protestors. If you want to stage a mass protest, rent a hall or find a field somewhere. You do not have the right to take over the streets of a city. That is confusing protest with mob action, which of course is the idea.
Our unelected rulers in the federal judiciary do not agree with me, but that doesn't make them right.