For example, I don't understand the Parable of the Unstoppable Mad Man. The author writes like it's obvious what the mad man is, but I'm genuinely confused.

The "mad man" is progressivism, demolishing the wall of the prison cell is something like "fighting for same-sex marriage" or "fighting against slavery" (or any other progressive cause that some random reactionary may be incidentally supporting) -- but if reactionaries help progressives in that one goal, then the progressives will move all the faster to some other more destructive cause that will have to be opposed.