"Communist bandit" is highly inflammatory rhetoric because it references the traditional Chinese term for a regime that has lost legitimacy and must soon fall: "bad men and bandits". It is roughly at the same level as "Fuck the King". Harmless words for people living in modern democratic states, but plainly out of line for people under authoritarian control.

I don't disagree with that. Though not clear if you were replying to my point about where the order to block it came from. Unless I missed it..

Is this guaranteed to be intentional or could it be an accident due to a poorly trained spam detector?

Could be, though I tend to go with occum's razor in most cases, which to me implies this is intentional.