A government has more than hegemony in relation to its citizen/subjects. Few governments are self-abnegating. The will to power exists in the people that are in government generally. The basic goal isn’t to create utopia unless that idea is defined as the ideal bureaucratic state. Taiwan is a free island-nation. It historically was independent of China and is likely to remain so even though it presently has a majority of ethnically Chinese people. Mainlanders often desire to oppress islanders and assert their tyranny.
In my opinion reckless Chinese expansionism is counter-productive to the general welfare of the mainland Chinese that endangers Chinese security and economic development. A respectful recognition of Taiwanese independence alternatively would enable peaceful trade and concentration upon ecospherically productive business and governing ventures and even joint efforts.
Today the Communist government has more similarity with the role of Nazis seeking to invade France or Poland. I suppose Hitler could have argued that he was just seeking the inevitable reunification of the Carolingian Empire disingenuously. The circumstance of Germany was quite unlike that of the independent nation of Taiwan. In fact the Dutch settled Taiwan before the Chinese (according to the wiki article). They imposed upon the native Taiwanese that were not a part of China.
The Qing dynasty did own Taiwan through invasion for a couple hundred years before the Japanese arrived and took it for themselves. The exiled nationalist government arrived eventually with the Japanese leaving. The Qing government was definitely not communist.
Virtually any independent democratic Taiwanese government would be more efficient and responsive to the people locally than the Borg of the Chinese Communist Party that is a swollen, economically prospering new power seeking to glom up everything it can.
Sure China had a civil war with two groups asserting the right of sovereignty. Ideally self-determination is the better way for political existence rather than coercion and subjugation beneath an authoritarian government. Taiwan though has a self-standing geographical identity apart from China, and apart from the claims to rule China. That old political split is a social phenomenon that cannot rightly be healed with even a semblance of justice if the rights and status of Taiwan and the Taiwanese were to be erased under authoritarian communist mainland rule.
Actually China is of course composed of a hodgepodge of peoples and nations built up since the Shang dynasty especially growing with the warring states period and the Chin dynasty following. Chinese rulers until reaching natural boundaries and terminal growth were expansive. Tibet was a free society until recently when China invaded and subjugated it. Justice in a new expansion would require that mainland Chinville take upon itself the name of Taiwan if the people of Taiwan wanted to be saddled with the problems of the mainland regardless of who the ruling powers are.
There is however no logical need for the Chinese of Taiwan to merge politically with the people of the mainland. Neither is there a need for the United States to merge with England etc. Racial lines need not require some sort of unified racial governance by the race anyplace on Earth.
Chinese communist leadership needn’t be concerned too much about western wishes for it to be politically regressive regarding territories. Fundamentally ‘western’ nations recognize the cruel subjugation of Tibet and the threats to Taiwan. Besides those issues China might be regarded as a nation of such immense population with such vast problems and challenges that the west may be thankful they don’t have any political responsibility for it. Capitalists of course like to profit from the Chinese human resources and consumption through sales and joint production ventures.
The historical western powers are also always concerned about increasing human rights in China and conserving human political and spiritual liberties domestically. Those seem to be threatened by purely secular authoritarian government expansion and socialism tends to undermine free enterprise.
That is all part of the challenging global situation where all 7.7 billion souls live, about how progress materially can occur with sustainable development even wile the ecosphere requires restoration as it is being rapidly depleted.