> Oh wait, this is discussion, not an academic paper.

It's literally an academic discussion insofar as it's about the technicalities of an academic paper.

So yes, you really do need to support your arguments if you want them to be taken seriously.

I've seen people say this a few times, and I think it is attacking a misreading of the comment (snarkily, to boot). Charitable interpretation: In a discussion, if someone says "Citation needed", it means "I'm skeptical and I'm asking for a citation" (which is quite reasonable), not "You should have supplied a citation before I asked for it" (which I would agree is unreasonable for statements one doesn't expect to be contentious).