Simplistic as usual, that "large section of the population" doesn't think "it's okay for the police to shoot unarmed black people during traffic stops and misdemeanor arrests" because they don't see the incident(s) you're referring to in the way you characterize them. They're being fed propaganda at the same rate you are, just by different sources and neither you nor they have the first clue as to what is really going on.
I think I've got a pretty good bead on it. Look, the point is, the Police in this country shoot 1200 americans every year. And yeah, most of those are probably "justified", even though other industrialized countries only need to shoot a handful a year.
But when we see a really outrageous action, like LaQuan McDonald, Phialdro Cruz, Mike Brown, and t here's still a bunch off you out there that take the police's side, people get upset.
Both sides are full of confirmation bias junkies that get off on the supposition that anyone that disagrees with you is evil, inhuman and immoral, the chattering classes know that and exploit it to the fullest.
I don't think that. I would categorize most Trump supporters as fearful and stupid. The One Percent has spent the last 40 years scaring the shit out of them, while diminishing their quality of life. They are smart enough to realize something is wrong, but too dumb to realize the root causes.