Not renouncing the use of force is entirely different than exercising it, which they haven't. This would be like calling the US imperialist because it wouldn't accept the south from succeeding pre-civil war. How

China's top official in charge of Taiwan policy, the ruling Communist Party's fourth-ranked leader Wang Huning, did not mention force in a key policy speech on Saturday, which instead focused on how both sides would benefit from "reunification".

So they aren't even threatening it, just not ruling it out. Again, not very imperialistic.