It’s a fair point. Systemic racism by police is a real thing, and the culture of silence and borderline extortionate tactics employed by police unions make it hard to change. Voters can say we don’t want to pay for that kind of institutional bad behavior. . . But all too often what we want doesn’t matter.
This is less of a free speech issue, and more of a "what should government employees be paid to do" issue.
It's the difference between a gutter punk wearing a swastika, and a cop on duty wearing a swastika. The constitution prohibits the government from making a law regarding the gutter punk. But while the cop is on duty, they're an employee of the state, and it's perfectly reasonable for voters to say "we don't want to pay government employees to do that".