My guess is that it's flagged by users. You can send an email to the mods hn@ycombinator.com to ask for more details. Perhaps they decide to disable the flags in this case.
This is actually pretty similar to the censorship being discussed here. If a thread, especially around these topics doesn't go as the moderators please, it is simply shadowbanned.
I hate the term "bootlicker" but it's apt for a forum that's more or less about people sharecropping on big platforms in order to attract investor money. That most people here think this sort of thing should be ignored is completely unsurprising.
This is a pointless and politically motivated distinction though. The moderators manually protect controversial articles with the correct political slant. Failing to act is entirely equivalent in this case.
It’s not pointless to correct a small misunderstanding. It is true that some articles here have been reinforced against flagging. I don’t have a political motivation to make these clarifications.
My guess is that it's flagged by users. You can send an email to the mods hn@ycombinator.com to ask for more details. Perhaps they decide to disable the flags in this case.