As a global citizen of Earth, I would agree. But I'm also a citizen of the United States, and have a vested personal interest in its academic and economic superiority. And I think that's normal. You don't even have to be nationalistic or patriotic about your particular country to feel that way. Academic and economic declines in any country will cause problems for everyone who lives there.

Of course there should be. However, those nations should worry about that on behalf of their citizens. No other nation is going to concern itself with whether Americans can live close to their parents.

Yup, the author is in a fairly rare fortunate situation for someone who is good in his field. A lot of us moved countries or continents to be good at our jobs, and there is always a personal cost.

Although, for grandkids, I guess that when you are far you are also more intentional with making sure you spend time with their grandparents when they are far.

There are plenty. The author is over exaggerating the prestige of CMU compared to other institutes outside of the USA.

Just in the western countries:

Toronto, Cambridge, ENS in France, the many max Planck institutes in Germany (eg Tubingen), the two federal institutes in Switzerland.

Faculty positions in any of those are likely to be better than CMU (in terms of start up package, funding, quality of students, quality of faculty, and ability to hire people).

Proof he's right wing? Source?

This is the sort of attitude that allows nations to fall. If a nation isn't protecting it's most valuable resources, they will be taken away by others who want them.