They asked for a citation, not evidence. A citation that cannot be provided as there was no quote in which to cite.
Furthermore, good faith participation seeks to provide equal value to the participants. "Citation needed" offers nothing to other parties.
Apparently, according to another comment, "Citation needed" is some kind of Wikipedia slang, but a website that attempts to document knowledge is very different to a casual conversation and to try and conflate them, again, can only be done so in bad faith.
Furthermore, good faith participation seeks to provide equal value to the participants. "Citation needed" offers nothing to other parties.
Apparently, according to another comment, "Citation needed" is some kind of Wikipedia slang, but a website that attempts to document knowledge is very different to a casual conversation and to try and conflate them, again, can only be done so in bad faith.