You aren’t brainwashed, you are just enculturated to a very reactionary ideology. I actually agree that it’s better to analyze them as separate countries for the purpose of something like this graph, but this thinktank (which, to be clear, is very Atlanticist, i.e. aligned with your geopolitical views) is almost surely gunning for having their little infographics be diplomatically palettable in hopes that they get used by important bodies.
I understand what you’re saying here and I agree that that’s what’s going here, but making something “diplomatically palatable” is for all intents and purposes equivalent to appeasement and (in my view) automatically makes any other claims made subject to suspicion.
I mean, Atlanticists are imperialists and should be condemned, but your view is rather unhelpful since it means the vast majority of statements connected to the UN since ~1980 fall under the same view. It’s not like the PRC denies that the RoC government exists and effectively controls the island of Formosa, in our context it is just a rhetorical affectation to the effect of the RoC government not being legitimate, which is a pretty fair stance to take given the RoC’s own positively absurd territorial claims.
The ROC’s territorial claims are a side effect of the PRC’s stance on Taiwan. I don’t remember the exact details but essentially the PRC has previously declared that it would interpret any change in the ROC’s territorial claims as a declaration of war. It’s a matter of pragmatism.