This is completely at odds with everything I've heard about US legal system, where the victims need to prove they didn't provoke the attacker ("stand your ground"), especially if the attacker is a cop, so citation needed.
Not quite sure what you need a cite on - That police in the US don't have the right to beat the shit out of you for no reason?
In theory, when cops give a lawful order, you need to obey it. When cops give an unlawful order, you can ignore it.
In practice, ignoring any order from a cop, lawful or not, will result in you having a very bad day. Resisting at that point will make your day even worse, from "bad" to potentially "dead".
If, however, you complied (note I didn't say "consented") fully, that drastically improves your chances in any subsequent legal proceedings, whether against you using illegally obtained evidence, or against the cop for abuse/assault/etc.