Seems like it would help keep the shorts from getting stinky.
Edit 1: friction is the answer
Edit 2: sorry for this edit – i was trying to make a new post, but Blorp for some reason took me to editing this one instead. Trying to put it back the way it was…


Same reason you don’t you wear underwear under your underwear.
I have lots of underwear, only few bike shorts.
I wear underwear to protect clothes.
I don’t wear underwear under underwear because i don’t need to protect it.
So it must be a different reason from that.