Beyond that, here in the USA, I don’t know anyone who I would consider both a “China apologist” and a “leftist” (“far” or otherwise) – China has not been anything remotely resembling socialist for at least a generation, and the China apologists I know all vote GOP (or would if they could vote).

Unless by “apologist” you just mean “has a low expectation that China’s political system is going to collapse or radically democratize in the near future, and thinks that some level of economic and diplomatic engagement is necessary despite China’s human rights record”.

"Why do that woman receive half of what that straight white dude gets?" - "Why are you asking? Why aren't you asking about the black dude get only a quarter?"

THAT is whataboutism. Implying you shouldn't make remarks (about a woman's wage, about Israel, ...) without also taking other cases (transgenders, blacks, China) into account is whataboutism: using a claim to fair and equal treatment as a way to avoid having to answer an isolated question.