The level of naked ethnosupremacism embedded in European ideals and their constant barking at how the US is actually the most racist country is so very funny to me. If you rebuild the ship of fools plank by plank will it still dash itself against the reef?
And yes, things like race are a primary reason (for good or bad).
And yes, as my Spanish friend keeps pointing out: While the US has a large homicide rate, they can't beat the Europeans when it comes to pogroms, mass killings, etc every so many decades. Europe will be, well, Europe.
If the very constitution of the country classifies tourists as "not subject to the law of the US", that's some The Purge level popcorn. All visitors and illegal aliens would have had diplomatic immunity.
The US can amend the constitution. It has not. SCOTUS has no legal right to do it unilaterally.