TSMC does not want to take any risks and ship Biden's supercomputer chips to China before it can verify that they do not break any U.S. export rules.
Taiwan and TSMC have done a good job fooling the West that they are just operating chip factories in Taiwan.
TSMC has many chip factories in mainland China. TSMC has a giant factory in Shanghai, right next to China's biggest chipmaker, SMIC.
Employees go back and forth between these companies all the time.
This idea that you can contain China's chip ambitions without restraining TSMC is ridiculous. If you want to stop China's chip ambitions, you need to stop TSMC too.