Sadly I have no argument for that...it’s certainly somthing we must stop doing. When my grandfather and his brother both left Italy one went to Canada and the other to The USA, lucky me.
There's nearly always some daylight between our carefully cultivated self-image and reality. In the case of the US as a nation, there's always been a LOT of it. We cover our simmering animus toward the Hated Other with a patina of Norman Rockwell wholesomeness but it's always lurking there, waiting to ooze out around the edges of our leaky abstractions.
The past is supposed to make us better, not cause us to repeat it! I am sickened by these events, and doubly disheartened by the fact it is happening again.