don't know about that.
Never seen female animals chee bye area have hairs. do you? Male animals lan cheow area also no hairs, can you explain that too?
Anything to do with friction?
My wild guess is human females have hairs and cheebye holes kept directly below so male animals do not get horny. Ask angmoh charboh ever their male dog get horny seeing her hairy pussy? And vice versa female animals push her pussy to human male to fuck?
I would think in those cave days, hairy pussy emit some kind of stink smells which turn off male animals and it wont get horny, teo boh?
The hair serves a purpose when screwing. It helps to reduce the fraction between both parties during the heated exchange.