"China" is analogous to "France," not "Europe."

There was a civil war inside China, with the rulers of both competing sides claiming the entire country as their own for decades after the shooting ended. Inside Taiwanese politics, there has been a shift relatively recently (in the last 20 years), but it would be a major shift if that were actually implemented as official policy.

> Many States may try to make claims for the title to support their legitimacy and heavenly mandate to rule, but that doesn't make it true.

We live in a post-WWII world of national sovereignty and inviolable borders (or at least we did until very recently). That's what China rests on for its claims, legally speaking.