Chinese people from mainland cares much less about democracy than citizens from western countries. The primary motivation for Chinese people to want reunification is that it's one of the last remaining symbols of colonialism.
Chinese people in Taiwan care A LOT about democracy, however. Despite the CCP's protestations to the contrary, there is nothing inherently undemocratic about Chinese culture, as Taiwan clearly demonstrates. The possibility that those ideas and that culture might spread to the mainland is a very real threat to the PRC's leadership.
Just so you know, I have friends and family from Taiwan. Some left Taiwan, and some stayed their whole lives. Some are KMT and some are DPP.
None of them want to reunite with China. Even the KMT ones just believe the KMT has a better plan for avoiding reunification. Some left Taiwan because they're afraid of a forced reunification. They care about democracy in Taiwan.
Of course Taiwanese people care about their way of lives, and they have full right to expect and defend that.
The problem is sadly much more complicated than "dictatorship wants to subjugate democracy". Simplified thinking is what the elites from China, Taiwan and the US wants you to think, so powers can be held onto and wars be justified.
Chinese people from mainland cares much less about democracy than citizens from western countries. The primary motivation for Chinese people to want reunification is that it's one of the last remaining symbols of colonialism.