>Pink Slime
Lustful, nature based slime girl. Well then… let me just get on my swimming trunks and dive in.

Slimes are just Slimes, they don't have a gender. They simply took on the form of a woman in this case because the audience isn't watching/reading for Men-shaped Slimes..

I share your sentiment, though.
I understand that they don't want to focus on monster guys, but I feel like it wouldn't hurt to show some more of them. The only Monster-men that I know have been shown in the series so far are Centaurs and Orcs (Pig men), both being portrayed as brutes, and fish-men. There's also the reference to Lizardmen and i guess we can assume there are Zombie and Cyclops men.