As a faculty member and PhD advisor, let me offer my reading between the lines. The student and advisor did not get along already. The student went to China and found a girlfriend. The lockdown separated them. Hormones flared, exacerbating what was probably already a tense situation.
The student was increasingly a problem (note the screaming at the advisor mentioned in TFA). The advisor decided that it was no longer worth the effort to maintain the unofficial relationship and broke the promise of supporting the student's future re-enrollment. Dealing with unprofessional students sucks. It's very hard to "fire" grad students for unproductivity or workplace issues, unless they are egregious. In this situation the advisor had a convenient out and took it.
The student was increasingly a problem (note the screaming at the advisor mentioned in TFA). The advisor decided that it was no longer worth the effort to maintain the unofficial relationship and broke the promise of supporting the student's future re-enrollment. Dealing with unprofessional students sucks. It's very hard to "fire" grad students for unproductivity or workplace issues, unless they are egregious. In this situation the advisor had a convenient out and took it.