Yeah it's a whole systemic thing, frankly there isn't really "one issue," but a multitude all working together. Stuff like no knock raids, qualified immunity, even just "one's tendency to stick up for one's friends" which we all have and we all do, but when you're the police force covering crimes it's a lot different than me clocking my friend in to work when he's running 5min late and doesn't want to be fired about it.

But as you say there are indeed plenty of good cops, though the "good ones" can't even do anything about the bad ones and so they end up being complicit or fired, making them "also kinda bad" or "no longer cops." That is another part of the phrase and why it's not "SCAB or MCAB, Some/most Cops Are Bastards," tbf.

It is a sweeping generalization, though, and as such it can never be 100% accurate by nature. Sweeping generalizations are too...general.