Why do we find farts/sexual organs/butts weird and edgy?

No.11468249 ViewReplyOriginalReport
I don't see a reason for disgust, as sex itself isn't disgusting, also it doesn't have that much disease.
>inb4 STDs?
Most of the stuff we see also have some degree of disease yet we don't joke about it.
Why sex? Why butts? Why farts?