> Not going to even mention the obscene difference in racism OR the language barrier, both of which are enormous factors.

Language wise, absolutely. Racism-wise, I think you underestimate how wildly racist the US is. As a European, I am still quite shocked. Everything in that country is viewed through the lens of skin color.

> No dual citizenship at all, most probably no citizenship.

Citizenship is basically impossible unless you are born to Chinese parents, but work visas in China are lightyears easier to get than the US H1B shitshow. In China all you need is an employer's invitation and you can more or less get a work visa, especially if it's for a skilled job in science, technology, or finance.

> Not going to even mention the obscene difference in racism

I'm non-white and I've felt far more racism in the US than China. That isn't to say racism doesn't exist, but it's much less.

> OR the language barrier, both of which are enormous factors.

Language is not a barrier unless you think it is. The IQ of people in China isn't particularly different than the IQ of people anywhere else in the world. If 1 billion people can learn a language, you can.

I doubt many of the researchers migrating even want Chinese citizenship and the chains that come along with it, so why do most people (presumably Americans) keep harping on and on about it?

Once you're invited by the CCP for your exceptional research background, you're literally given an open chequebook for both your personal compensation and your future research endeavors. You're allowed to take your family along with you too, and the language barrier doesn't translate in the professional setting. Racism is a non-issue since I doubt these researchers will even be interacting with elements of that segment of Chinese Han society, unless they choose to.