It's a bit more complicated than I implied because many or most Taiwanese prior to the beginning of KMT rule were still ethnically Chinese; they just hadn't been part of "China" for 50 years (a period when there wasn't a stable, unified "China" anyway). "Occupation" is a controversial term for the period of Japanese rule and the Japanese weren't "hated" in Taiwan to the same degree they were in other occupied territories. The period of Japanese rule from 1895-1945 was a colonial government, but it was probably better than what was going on on the mainland at the time--domination by Western powers, the warlord era, the civil war, and a much more brutal Japanese occupation. The difference between Japan's treatment of Taiwan and mainland China is a big part of the difference in perspective towards the Japanese between the mainlanders and the Taiwanese.

Some of the main proponents of the "Japanese occupation" narrative are the KMT, who committed plenty of atrocities of their own after taking over Taiwan and, among many Taiwanese, ended up more hated than the Japanese. The KMT was also serious about their lost cause of retaking the mainland, at which point they expected Taiwan and China to remain unified under their rule, with the famous "One China Principle" representing not just the CCP's desire to control Taiwan, but the principle shared by the KMT that Taiwan is part of China and should be under the same government. In recent years, the KMT has pivoted towards cooperation with the CCP with an aim towards peaceful reunification, while the DPP favors explicit Taiwanese independence (Taiwan's official constitutional stance still being that it is the legitimate Republic of China).

To be fair to the KMT, they also ushered in Taiwanese democracy. When Chiang Kai-shek died, his son and successor Chiang Ching-kuo ended martial law, promised to be the last Chiang to rule Taiwan, and began the transition to democracy. His successor, Lee Teng-hui, was Taiwanese-born and finished the transition to democracy, winning the first democratic Taiwanese presidential election in 1996 before stepping down at the end of his term limit in 2000, at which point power transitioned to the DPP. Lee was also controversial with the hardliners in his own party for, among other things, his more sympathetic attitude towards Japan.