I'll say it again: Why would countries risk ruining trade relations with China, one of the three most important trade powers internationally, over unnecessarily pointing out reality and thus contradicting China? And how can you seriously say territory a country doesn't control in any capacity at all theirs? Why do you think a majority of world powers are independently trading with Taiwan if Taiwan isn't independent from China?
Don't you think China would, you know, not be constantly complaining about not having control over Taiwan for the past few decades and making bluffs about invading if Taiwan were already part of China? That's a pretty obvious sign that "no, China doesn't own Taiwan in any capacity".