I’m not sure how “PC-ness” is part of this at all. “Liberal DAs”? That’s an oxymoron.
The reasons cops keep getting away with crimes — both large and small — are several. First, their unions have successfully negotiated contracts that basically give them total immunity — in Schaefer’s case, Wilton Manors PD was forbidden to put his infractions on his record. This enables cops like Schaefer and D’Angelo and others to simply move from town to town, with no one knowing what they might have done in their previous job.
And the police departments themselves, all too often, cover for their “brothers in blue.” The judicial system, too, sees them as partners, and typically either refuses to prosecute at all, or when they do, the criminal cop is given a slap on the wrist — like Schaefer being given six months for kidnapping, raping, and torturing two girls. And allowed to walk free for several months before turning himself in (during which time he killed at least four more women). I don’t know of any other violent criminals allowed to choose when they go to prison.
The final point is, there is little to no public oversight or accountability of police, which is the big thing the marchers are demanding. You’ll notice the folks bashing (both verbally and literally) the protesters aren’t liberals or leftists. Go to any “Blue Lives Matter” meeting or Facebook group, and see how “PC” they are.
The right wing, despite its supposed love of freedom and small government, LOVES them some heavily armed police forces (as long as they’re aiming all that firepower at hippies/leftists and communities of color, of course).