I have seen zero evidence this was a hate crime at all. People are just assuming it was racial because like I said this has turned into a political shitstorm.
It's possible the officer had some sort of beef with the guy in particular, or he could just be a shitty cop. I doubt we will ever know because no one seems interested in investigating this further, probably because they are worried if they do people will think they are looking for excuses for the cop or something.