If Narcissus had been a woman and Echo a man, then we would correctly analyse the story as a misogynistic exercise in heteropatriarchal norms. Modern readers are only able to empathize with the Hellenic view that Narcissus owed other people love, because the heteropatriarchy erases asexual men and maintains that all men are naturally creatures of sexual desire. This is not only aphobic, it contributes to misogynistic rape culture and it degrades men by reducing them to the social role of sexual monster. A role some men take seriously, and to the extent of normalising sexual violence against women.
In making space for men to exist without the pressure to romantically or sexually perform for (or violently against) others, we see that Narcissus is rightfully entitled to his own feelings. Echo is guilty of romantic assault, seeking to make him hers, according to a fantasy she developed in her head while stalking him without his knowledge. Echo fails to respect his right to consent in her heart. And so does the nameless suitor who prays to Nemesis for the act of divine intervention that lead to his death.
Narcissus does not owe his allosexual suitors a polite rejection. From the content of his life, we see that he was constantly sexually harassed, and indeed sometimes violently so. And he was 16, for Dionysus' sake! He was just a kid! Some boys haven't even hit puberty yet at that age. And given the Hellenic idealization of the beauty of male youth, I daresay Narcissus may have been one of those boys. And no 16 year old, regardless of bodily maturity, deserves to be subjected to such sexual harassment. No adult does either, but it's particularly disgusting in the case of a boy like Narcissus.