The tendencies are probably there in all of us, to some extent.
But training that is legitimatized by a society determined to maintain white privilege by ANY MEANS brings the brutal and sadistic tendencies out. And constant exposure to other's with like attitudes in an environment that condones and encourages brutality continually reinforces the mind washing.
This is by intent. US society has encouraged and legitimized this systemic and violent behavior - and most people support it because the meme is continually pushed through the MSM that aggressive police are 'good' for society.
White Folk have demonized 40% of our population (soon to be 51% in around 15 years) for 400 years; and put the brutal enforcers of that demonization on pedestals and showered them with respect and flowers.
Instead, the innocent oppressed have been demonized by society.
And most POC have to a large extent bought into this enshrinement of police blue as 'respectable' over the past few centuries, since they 'protect' the 'law abiding' from the violence that the exact same systemic racism has caused in their impoverished communities.
Only the righteous rebellious like Dr. King, Malcolm X, Rep Lewis, Bob Marley, BLM, Stacey Abrams, and others of like countenance have continued to fight against this misplaced trust in authority, god bless their hearts and souls.