Neptune

neptunic means being a dude attracted to men (or just masculinity in general, i'm not sure)
kinda like how sapphic (wlw) was named after the poet sappho, who was a female poet who dated women. (she also lived on the isle of lesbos, which is where the word lesbian came from)
planets are often named after people from mythology
so my guess is that the god neptune liked men

.....jesus christ

someones done their research

yeye