For starters, let’s be clear: Jacob Brown committed battery, a violation of Louisiana state law. This case is about an alleged violation of Federal law and simply isn’t a battery case. That means it’s not as cut and dry as “we have this guy on video committing battery with a flashlight, of course he’s guilty”.
So if you want to claim this case is open and shut or cut and dry, you need to point to some element of that law Jacob violated and then explain how it’s so obvious he violated that element.
My first guess, and to be clear, I am speculating, is that they tried to prove Jacob battered Aaron because Aaron was black. That means proving beyond a reasonable doubt that Jacob doesn’t simply beat everyone up, which is very difficult to prove, especially since so many cops genuinely do simply beat everyone up.