Are you blind or willfully ignorant? There is no rhetorical purpose for it, there is the simple fact that Kuomintang is the name the party themselves have chosen to use as their English name. It is not up to any outside party to decide what their name is.
No, your point fails. when those words and names were first used in English, were they common nouns? No. Did they mean anything to English speakers originally? No. And If they’re all now common nouns, go on, tell me what Mana Motuhake or Tinorangatiratanga are, without a Google. Go on. Just because there are a couple - deliberately chosen - in that list everyone knows is irrelevant.
It is incorrect if you are referring to them by that as a name, but not as a descriptor.
No more than you need to speak Arabic to know what Al Qaida is.
No, they are wrong in doing so, because they are choosing deliberately to translate the name rather than use the official name.
As Poagao and I have said repeatedly - who are you, or we, to decide what another party’s name is? Are you trying to say that the Kuomintang are wrong when they say their own name is the Kuomintang in English?