Maybe facial hair just isnt stylish enough for them.
And wierd; on the topic of hair dicks transmitting stds, i would retort thar it is only reasonable in such an ecosystem that organisms have a strengthened immune system or other self defense mechanisms around these vulnerable areas for precisely that reason. Take life on earth for example; reptiles and birds literally put it in the bum because thats where their reproductive organs are meant to be accessible from, but they typically dont get life threatening infections from it; if they did, theyd all go extinct or some freaks with genitalia separate from their GI tract would be the dominant, most common phenotypes on the planet. Which we have... maybe the dinosaurs did die of stds? Who knows.
These diseases would be common logically, but arent the focus of or even an important element of the story so far, and yeah nearly nobody in hollywood understands biology anyway id figure
Here's the deal though. You have that scene where blue chick tells magic white guy all about
The birds and the bees how to use his hair tentacle to get the feels of his "totally not a horse." Now, was there any kind of realistic "Now, before you do that, check the bundle for funky smelling discharge" or "Check for the mad-rot" or some other actual, beneficial tribal advice?
NO.
Indigenous aboriginal peoples with very shamanistic cultures have lots of such folk-wisdom, and the passing of that knowledge is part of being part of that culture and tribe. (the act of transmitting that knowledge to an outsider would, in and of itself, be a major sign of trust and acceptance) Again, there is a conspicuous lack of this. This was an opportunity for a deeper, richer narrative that depicted the Navi as more than just Magic Space Indians. It could have depicted more than just superficial culture staples-- it could have given insights into the clearly very imaginative fauna and flora of the planet, but no. Gotta totally cut that world development for some blue chick nookie action and thinly veiled bestiality.
Again, I saw it as "Hollywood has no idea what they are doing." along with "Typical movie goers likewise do not know what they are doing." resulting in a disgusted feeling of "Gawd, this is horrible drek, and saccharine pablum all in one bottle. Gross."