It's pretty common for people to throw out "citation needed" when they don't want to believe or admit something, but can't plausibly deny it. Sort of the same way people use the term "fallacy" these days.
IMO "Citation needed" is a quick way to say "do you have a source for me?", and "fallacy" (hardly used without also mentioning the specific fallacy) is a quicker way to say "I recognized logic flaw X in your argument".
You are free to see harm in these statements but telling me they are always meant as harmful as you mentioned is your own negative reflection. Not mine or ours, we are free to have our own interpretation as well.
I think citation needed carries a connotation of “I don’t believe this is true.” It is just a lazy way to converse if you are engaged in a genial conversation in good faith. “This is new to me, can you share some references?” I appreciate we can be technical and to the point, but given the context, I felt my response was appropriate.
I do understand you interpret it as "I don't believe this is true" but my explanation "do you have a source for me?" is also a likely explanation. If I then apply the HN rules where the reader must assume good faith and interpret posts in the most positive way, I'm leaning towards assuming "do you have a source for me?"
