butt sweat

i go to the gym in what equates to pajamas. they're stretchy and black and usually smell (bad). last night after i went to the gym i pondered something. how come when i used to go sit there reading books while my mom worked out, did people wear things like this.

i'm just one of those people who prefers not to have things shoved up my butt while i'm doing other things. what i mean is, if you're going to shove something up your butt (i'm not saying i do), it's usually for that one purpose. like enemas, butt sex, colon doctor things, etc. not like, "i'm at the gym AND i want something up my but." it almost appears in this photo that it's a picture of a front. the front of a woman with either a very dark complexion or one who forgot to go to the waxer and opted for the ever popular legging underneath.

back to the point, why did people ever wear these to the gym?