I didn't do any particular research here, because it conflicts with the preexisting knowledge I have about the subject, and because my experience tells me that figures like these, which can be, and especially when they actually are used to further political narrative, are often misleading, and/or wrong. However, I didn't want to accuse the commenter of any bias or misconduct, hence I phrased my question to leave out my skepticism.
The truth of that part isn't important. It's the fact that it's a good faith hint.
You actually hit the spot: you can assume good faith when sitting around in uni and asking people to help you calculate Galois groups. You cannot assume good faith when talking to strangers online on politically charged topics: even if they are themselves operating in good faith, it is highly likely that they were fed, as you call them, "hints", by bad faith actors. Hence, I ask for sources.
I noticed that most people who really know their field don't cite their assertions. It makes sense. So now I'm not surprised when people don't provide a citation.
That's because they can rely on their authority and experience to establish trust, and they have reputation to protect in case their assertions are actually completely wrong. None of this is true when talking to random, anonymous people online.
To me a forum like this is like when I'd be sitting around in uni wondering aloud about some problem and someone will say "Well, maybe if you use the fact that the functions which invert the sign of the √2 and √3 parts in Q(√2, √3) are automorphisms, then you can see that the group containing them and their composition is just Z2×Z2".
The truth of that part isn't important. It's the fact that it's a good faith hint. It's my job to go find the truth given this mild heuristic.
They're the ones doing me the favour so I have to contribute in order to get more information. In this case, I can attempt to find an error in the proof or to ask clarification. But if I were to ask them to write out a proof then I'm being a fool and I'll get fewer hints from them in future.
I noticed that most people who really know their field don't cite their assertions. It makes sense. So now I'm not surprised when people don't provide a citation. It's just a hint. They didn't sign up to be my tutor.