What people consider themselves is unimportant. Taiwanese is not an identity, it's not a culture, it's not a nation. Just like the Confederacy isn't a separate nation and the people who identify with it aren't a separate nation. Identity is historically and communally constructed. The history of Taiwan under the KMT is literally the history of a Chinese military executing a terror campaign for 4 decades and collaborating with imperialist powers. That's it. That's the history. That doesn't make a separate culture, it makes a separate political group. There's a big difference.
Taiwanese IS a separate culture, but only in reference to indigenous Islanders. Calling the genocidal KMT "Taiwanese" is as bad as calling the occupying white French people in Haiti "Haitians" or occupying white English people in Jamaica "Jamaicans" or occupying white Americans in Hawaii "Hawaiian".
The REASONS people don't want to be part of mainland China are illegitimate reasons, just like the reason for the Confederacy to secede was illegitimate. The REASONS people in Taiwan don't want to be a part of the mainland include: the KMT killed everyone who wanted to be a part of the mainland, generations of people were traumatized by the mass murders and taught their children to believe things based on that terror, Western imperilaists propagandize the island relentlessly to move public opinion towards Western interests, Western imperialists have created financial incentives for the upper class in Taiwan to adopt a pro-Western stance to support Western interests, Western imperialists have meddled in the political and cultural affairs of Taiwan since the KMT fled there to create political conditions favorable to the West.
None of these are legitimate reasons for Chinese people in Taiwan to claim a new identity. Also, none of these are sustainable reasons, which is why China will only invade Taiwan if the West moves to create new military threats via their control of the island. Without that provocation, China will integrate Taiwan slowly, by creating incentives and decoupling Taiwan from Western interests. As the dollar collapses and US economic hegemony falters, the incentives will start to drop. As China continues its counter-intelligence against the US and continues influencing Taiwan and the region, Taiwan will move towards the mainland over time. The West must not interfere with this process.
And you're wrong that people want to go into Taiwan and take people's home. China is very clear - one country, two systems. The people on Taiwan stay there, but they would no longer have Western military bases there. The Chinese military would defend Taiwan as one country. The foreign policy stances would be decided by the party and include the interests of Taiwan against the West. Laws in Taiwan would remain the same at first and through democratic processes, the people of Taiwan would slowly integrate their system and the mainland to create the best system possible.
None of this is taking people's home. China operates the most complex multi-ethnic multi-system country in the world. Unlike how when the US comes in and colonizes, China has demonstrated for decades what coexistence and autonomy look like.
You imagine you have an enlightened political position that sees both China and the US as evil. You think you have any reasonable opinion on China despite being totally ignorant of the country, it's politics, and it's history. You think China represses those they consider less worthy while it is currently the world leader in multi-ethnic autonomy. You think China has a privacy problem despite all of the revelations about the West's truly complete domestic spying on literally every thing including doorbells and baby monitors.
You are ignorant, and you use that ignorance to develop an imagined political stance that literally only Westerners hold. There are no other people in the world who think your position is reasonable, let alone informed. It's a purely western construction, emerging from systemic Western propaganda and individual Western ignorance. The more you study China, the more your position will change.
I would know. I used to believe what you believed.