Didn't you know that being shifty is now a crime in the United States of Tyranny.

No, it is not okay to assault a police officer, but why was the officer attempting to question this guy before he had done anything wrong?

Being shifty and nervous should not be grounds for the cops to harass someone. And when they are harassing the public unnecessarily, what exactly are we supposed to do about that? If you complain to their supervisor, you are treated like a criminal. Maybe, next time this cop is thinking of harassing someone who hasn't done anything yet, he'll delay a bit and consider whether his "intervention" is really necessary.