On what basis do you say this?

Here’s the constitution of Taiwan in which they state they are the Republic of China — are you suggesting they aren’t part of the country they claim to be?

There has never been any doubt since the USA handed the Province of Taiwan back to the KMT after the Japanese were forced out at the end of the Second World War, that it’s a part of China. Historically and geographically, just not politically.

Ask a Taiwanese person what they think, I know many and they all agree, it’s part of China. Here’s the legal position, supported by the USA and the UN among most other countries. Not my place to argue with them, I just follow international laws