Mainland China regards Taiwan as a province that has revolted, with no right to existence as a nation. So China's response to anything that supports or gives respect to Taiwan is pretty predictable.
FWIW, in the 20th Century, mainland China had governing control over the island of Formosa/Taiwan for a little more than 4 years, from when Japan surrendered it in 1945 to December, 1949, when Chiang Kai-shek moved his government from the mainland to Taiwan. Japan had acquired the island in 1895, in the settlement of the First Sino-Japanese War.