You go on vacation to enjoy yourself. It's hard to enjoy yourself when you are embarrassed. Why don't you think this is rational?

Plenty of US citizens are canceling their vacations because they are afraid of reciprocity of treatment by immigration and people in other countries. And some US citizens, yes citizens especially immigrants & minorities, are also worried about abuse by border patrol upon their return.

No one wants to go on a vacation where they have to deal with unnecessary stress.

My wife and I were in Greece while the inhabitants were angry at Germany for the freshly introduced austerity measures. We sometimes spoke Flemish to each other, which for them sounded like German. We got some anger directed at us a few times from random people around us, and a shopkeeper stormed outside and threatened us with violence, completely unprovoked . We were very confused, we didn't know what we were doing wrong, and never saw that on previous visits. When our penny finally dropped and we made clear everywhere we were from Belgium, not Germany, the mood lightened considerably and we got apologies.

It might not be wise to loudly declare yourself American in the EU or Canada right now.