But there are people who identify as left-wing who will support China and Russia while downplaying their authoritarianism.

That's not something being invented as a boogeyman. Anyone can go to lemmygrad.ml right now to see it in action.

I've seen Sealioning used quite a bit in a particular Lemmy instance that would self describe themselves as Pro-Russia & Pro-China, as a way of shutting down discourse between people who disagree with them. There are people who disagree with a particular narrative, and they're discounted immediately for wanting to know how someone would arrive at a pro-Russian & pro-China position.

Also they'll just "whatabout!" and change the subject whenever unassailable critiques of these regimes come up. As if its is only possible to hold outrage in a single direction at a time.

I'll have you know I'm capable of disliking EVERYONE mentioned in a given conversation.

Yeah and as smart as anyone is, they aren't right all the time. As much as you can agree with his messaging, it's important to critically assess everything said, regardless of who is saying it.