yes, it’s obviously transphobic. He’s pissed a trans dude is better at sex because he assumes the trans dude is inferior for the genitals he has (i HaVe a PeNis y FeMalE no FuK mE)
Mate, it’s 4chan, 99.9% chance he’s transphobic and overall a bad person.
Were it just a twitter/tumblr rando saying “ey I feel owned cuz my FTM roomate does the heterosexual sex way better than me” it wouldn’t be funny, cuz this has the seasoning of the person whining being a bad person.
It’s okay to feel frustrated about not being good at sex (it’s not the butt of the joke here). But it’s funny when bad people gets salty.