I haven't watched the video, but as to the question you're posing, it's not so black and white. But yes, because cops monopolize force and use it against you to protect the interests of the state. Very few of them break ranks when they're told to oppress citizens.

Cops are necessary and they're not bad in a political vacuum, if kept in check with regulations, but under a hostile regime they are little more than troops mobilized against the citizens they're supposed to protect.