But even back then, some groups of people were treated badly by the local police in some areas. Now it seems the bad treatment is has become "DEI" instead of good treatment expanding to everyone. :(
Ref for non-US people and the very young:
[0] https://naacp.org/find-resources/history-explained/origins-m...
[1] https://nleomf.org/slave-patrols-an-early-form-of-american-p...
Cops have always been this way.
I think a large amount of the danger American police face is due to how easily a single arrest can ruin your productive life. One facing the loss of their home, pets, job, important documents, sentimental items might not see the difference between losing everything, and losing everything and taking the guy who's taking it from you, with you.
If we had an actual system based on reform rather than punishment, I think the danger police would be in would be greatly reduced.
You also have things like qualified immunity and general protections for police against being sued for an unlawful arrest. An officer can incorrectly arrest you and you could lose everything and be simply shit out of luck.
If there's no repercussions for bad cops, there's no justice. If there's no justice, why would one play nicely with the law, therefore police are in danger.
I don't think it's that complicated. Rather, I think that a lot of cops think they're in more danger than they really are. The vast, vast majority of people aren't going to gun them down for a traffic stop or for providing a warning about something. The situations where they're likely to get shot are exceedingly rare. By treating policing as some tremendously dangerous job we're completely ignoring the actual statistics, which show that firefighters and construction workers are far more routinely in physical danger.
The police then get carte blanche to walk around treating everyone like some dangerous creature ready to explode at the slightest provocation when most of us are just trying to get by and are pretty accepting of the benign law enforcement interactions we get.