The myths say Narcissus rejected Eros and all lovers. Ancient Greeks didn't have the word "asexual". Expecting them to describe things in modern language is a failure of your ability to interpret things from their point of view and understand cultural differences. You're holding ancient peoples to an impossible standard. The work of a historian or archaeologist is to understand ancient cultures well enough to interpret their words, and not to take everything literally.

There is no evidence that Narcissus was allosexual. What you're doing is treating straight as the default, and demanding an unreasonable standard of proof to confirm that a character is queer. You've internalised queerphobia. And the reason I was aggressive with you, is because you began by attacking me and calling me queerphobic. You seem to have calmed down, so now let's talk facts. Narcissus displays zero evidence of any sexual or romantic desires in the text, except for when he's being cursed by a god who was told to make him love.