I'm just amazed how high it is. Living in Europe, and reading "43% in the U.S. say they display the American flag outside their home" ... wtf. Is there any European country that has 1% do that?
News flash: other cultures are different than yours. People in them will do things that you don't do, or not do things that are extremely common to you.
I dunno about the rest of the country but take a stroll through Madrid. I have never seen so many flags on display, especially around and near a city center. The number of Spain's national and civil flags around the city and hanging off apartment balconies was surprising.
In the US flags are generally in the suburbs where the houses are (not so much apartments, leases usually prohibit it). In my experience (Texas, USA) I see more college and state flags than American.
In Canada, the right wing loves to fly lots of Canadian flags.
At the same time one of Pierre Pollievre's main slogans was "Canada is Broken".
He dropped that slogan after Trump made Canadian pride cool again, but the sentiment is still there.