this is not unique to the US, it is world wide. There are always a percentage who either enjoy (sadists) inflicting cruelty; or who are really good at turning a blind eye to it.
They tend to be extremists and usually (not always but usually) they are right wingers. History is riddled with examples from the pogroms in Europe which occurred all over since nation states began, to trans-Atlantic Slave trade, to the destruction of the native peoples of America by the Spanish and English, to the continuing of chattel slavery in the US until the mid 1800's, to the Armenian genocide, to the Holocaust, to the "terrors" in Stalinist Russia and Maoist China to the insanity or Pol Pot's Cambodia. Remember the punitive response by many Americans to the drug war against Black and Brown people (as opposed to the outcry about the opioid crisis affecting White people today), or how Reagan turned LBJ's "War on Poverty" to a "War against the Poor" by calling out "welfare queens" and "young bucks"? The refugee crisis in the Northern Triangle didn't just start during Trump's administration, it started during and even before when Reagan backed right wing death squads to terrorize Nicaragua, El Salvador, and Guatemala to keep them from instituting the democratically elected socialist reform governments in the 1980's. Those civil wars lasted at least a decade and they still have not recovered.
A lot of Americans don't know or don't care about that history. They think that the refugees somehow deserve what they are getting for being born into messed up countries and not "fixing" them.