I think this has much to do with the history of policing in the US which originated in the South as re-enslavement patrols and in the North as strikebreakers [0]. these institutions were built to be oppressive towards a population that was heterogeneous. this is unlike the ethnic homogeneity in Europe

with the recent waves of immigration into EU states, you're now also seeing some of the same tactics in use by those 'better' policing institutions (eg France's prison population [1]) plus the rise of reactionary, far-right political parties [2]

my guess is that these are just the natural outcomes from us organizing ourselves as nation states ruled by ethnic and economic elites. carve up borders along sociocultural lines like shared language, religion, and phenotypes and you will always have a ruling majority (at least in the beginning). any changes to that status quo means someone has to relinquish power and some people will do everything, even deliberately antisocial, societally harmful things to preserve that hold [3]

until we move past this kind of organization, I don't see any other possible outcome. given the mass migrations that will occur due to climate change, I expect we'll reach a breaking point within a century and the only path forward that isn't regressive will need to be revolutionary rather than evolutionary

[0] https://sandratrappen.com/2018/11/18/private-police-forces-t...

[1] https://www.antoniocasella.eu/nume/France_prison_MUSLIM_2008...

[2] https://www.dw.com/en/far-right-populists-eu-germany-afd/a-7...

[3] https://en.wikipedia.org/wiki/Southern_strategy