Well that's one take on it. From the western perspective Taiwan was part of China and when the communists overthrew the government in the mainland with military force it retreated to Taiwan. Now Taiwan is effectively an independent democracy and the commies want to overthrow its government militarily against the wishes of the locals as usual. The world's democratic governments generally oppose the overthrow of democratic governments by dictators who want to grab some place by killing the locals.
A civilized compromise might be a union like the EU with both governments continuing on an equal basis.
A civilized compromise might be a union like the EU with both governments continuing on an equal basis.