There's no reason for xenophobia.
Plenty of ethnic Chinese and Indian people become or aim to become US citizens, and contribute.
30-40 years ago it was Russians, Israelis, and Japanese who were the stereotypical foreigner in graduate STEM programs.
You'll also notice a direct correlation between Chinese visa backlogs and the rising return of Chinese expats to China in the 2000s.
A similar thing happened to Israelis and Koreans in the 1990s and is starting to happen with Indians now in the 2020s.
The economics of doing graduate school as an American just don't make sense (outside of those closely affiliated with DoE labs).
For a foreigner (Indian, Pakistani, Chinese, Iranian) the incentive of getting a path to naturalization along with degree normalization is enough incentive (as you yourself probably know).
No American employer is going to hire a LUMS or UET graduate directly, and if you don't want to work in the Gulf or in Pakistan, your only option is graduate school, especially because there aren't as many MNCs to sponsor an L1/2
Top tier foreign talent gets brought directly via L1/2 programs (like my parents a couple decades ago) as MNCs will transfer the cream of the crop to HQ.
In cases like Pakistan and increasingly China, where MNCs don't have full ownership or are non-existent, the only path is graduate school.
Same thing used to happen to Israelis and Indians in the 1980s.