While the data you present are interesting, and I can see how they could be a factor for an immigrant to choose America, I don't think they correlate with welcomeness to immigrants as much as you imply.
In the EU, countries have a relatively strong ethnic identity, with differentiated languages and cultures (some of which are perceived as endangered, in particular by American influence), while America is a melting pot and its culture is less differentiated basically because they have exported it to the globe.
A Spanish person could think that if you don't speak perfect Spanish, eat and cook Spanish food, have lunch past 2 PM, frequent bars, stay out until late, talk loudly and eat jamón serrano, you are not a "real Spaniard", because you are not like them (I'm using hyperbole to get the point through, of course not everyone in Spain does all that, but I hope you get the idea). But does this mean that they won't socialize with you, consider you for dating, or give you a job? Of course there are racists and xenophobes anywhere, but in general, i think the answer is not at all. Many won't consider you a "real Spaniard" -not me, I would say yes to that poll, but many wouldn't- but they will be happy welcoming you, and consider that the cultural differences are a good thing as they can learn from you.
On the other hand, in the US most people will consider you to be a "real American" because in America ethnicities and cultures are much more mixed, so it wouldn't make sense at all to think that you need to have a certain culture or customs to be American. But what's that good for in practice? Probably the cops that kill black people arbitrarily consider them to be Americans (it would be hard to argue otherwise when they have lived in the US for generations), they still hate them and shoot them. I have friends in cities like Baltimore that tell me about totally segregated neighborhoods, what does it matter that people consider their fellow countryman of different races to be American if they don't mingle with them? And that's without even talking about a president who fits more into your own words "right-wing nationalist" than almost any EU president, with an erratic immigration policy that scraps visa programs on a whim, something that I've never seen in Europe.
My feeling is that the reasons for many emigrants throughout the world to choose America are more sentimental (based on the inercia of the US's reputation, romantic ideals in movies, and general hype) than rational. I have seen this live often. I have seen Iranian candidates reject a job offer here to go to America because you know, it's America, to earn much less, have a worse standard of living and be travel banned on a whim of the president a few months after taking the job...
That said, don't get me wrong, I wish you and all the people who emigrate to America the best. It has worked fine for many people and will keep doing so. I just think it's overrated, and other destinations (not just the EU) would work as well for most people. To each their own, though.