This should go into a new catagory called “SHIT I AM SICK OF SEEING.” But then the organization would be screwed up and that’s another thing I’m sick of seeing.
Female is an adjective. Male is also an adjective. It’s something you use when describing the gender/sex of something else. So, for instance, my beloved pet parakeet, fondly nicknamed “Chicken Butt”, is a male parakeet. If I referred to him again, I would note that males of the species (again, using Male to describe the parakeet) have a blue cere.
If I were to simply say “MALES, Y U DO THAT?” you would be justified in asking me, “What kind of males?” since I was needlessly vague in my statement. Additionally, I am assuming that all males do the same thing. It’d be like me asking “WHY DO ALL MALES HAVE BLUE CERE?” It’s inaccurate and it assumes that you crap all over everything every 15 minutes (much like Chicken Butt).
When you say “FEMALES Y U DO THAT?” you are being needlessly vague, additionally, you are assuming that all females, everywhere, of every species and culture, behave in certain ways or have certain characteristics. It’d be like asking “WHY DO FEMALES BITE THE HEAD OFF MALES WHILE THEY’RE HAVING SEX WITH YOU?” when that’s only applicable to a certain species of insect.
So in short, stop it. Use nouns after your adjectives. Males and Females are also not all a like. If you wonder why women get all bent out of shape, in your not so humble opinion, when you treat them like they are all the same, just remember that men are not a homogeneous class either.