Honestly, if I were a professor and my PhD student was overly critical of the US online, I too would distance myself. Visa applications are hard enough as they are.
Eh - I knew Arab students who couldn't get their visa renewed for some years after Sep 11. They were involved in antiwar protests, etc. The fact that the US put many of its own anti-war activists on no-fly lists despite not having any evidence they were threats makes this pretty easy to believe.
Happy ending here: he was admitted to the country a week later, on his second attempt, in time to start classes.
(I'm not making excuses for the---dire---state of our immigration policy as a whole. But I was happy to see that this particular case worked out in the end.)
The article mentions a single tweet with a comic depiction that includes possibly exaggerated Asiatic features. Whether this kind of thing qualifies as “racist”… opinions may differ, especially since the article does not provide the original image.