There are 2 outcomes here:
1) You get shot immediately by the police, chaos ensues but at the end of the day you're still dead.
2) You shoot them, harm/kill them and if their colleagues don't shoot you back there's still more than enough proof out there to bring you a lifetime of legal troubles, especially considering "self defense" laws don't apply when it's against police.
In both cases, you're either dead or in the shit and nothing gets fixed. The US already proved that they couldn't give a shit about police brutality (otherwise we wouldn't have these protests to begin with) so more civilian kills on the leaderboard is just a drop in the bucket at this point.