Those people were idiots, not roleplayers. Because I really hope that a roleplayer would a) be able to read and understand the word Roleplay, and b) understand the single most basic principle of roleplaying. Other than that, I really hope they only played as humans with the same job they have in RL - anything other would be extremly hypocritical. If I were in a bad mood when they sputtered such moronic bs towards me, I'd probably ask them why they play as pretty people in that case.
In SL, I don't really have experience with using a male avatar. I have a male alt, which exists soley to look pretty for me, and to log into when I, for whatever reason, am unable to log in with Sukubia. My best friend switches genders a lot, although on one avatar, which started out as a male while she herself is female. She usually get's ignored when male, and hit on when female, and that's about it.
The only experience I have with playing as a male, is from roleplay in wow, where I sometimes do play a male character. Good enough to get swarmed with ladies who missunderstand rp with a dating app and get super angry because my guys aren't interested in the low hanging fruits, heh.
Also, why would anyone be unable to play as the opposite gender. Boogles my mind.