Why do most humans have have body hair around their genitalia and anus?

I have never seen a satisfactory explanation of this. If body hair is around the genitalia and anus to help guard against friction, such as perhaps under the arms, then why do men have hair on their faces? I can understand the evolutionary benefits of head hair (the sun, etc.), but if facial hair has an evolutionary health benefit, then why don't women have facial hair? And if genital hair has something to do with sexual attraction, pheremones, etc., then why is it also in the anal area?

Why do most humans have have body hair around their genitalia and anus?

Evolution is an unguided process which sometimes picks the best-adapted packages of genes (individuals and perhaps groups or species). That means not every trait is optimized. Also, since evolution is wasteful and messy, traits aren't tailored to the organism (anal hair, vestigial hair on knuckles).

There is always some genetic baggage.

Also, there are many traits which are sequelae, sort of like genetic side effects. High circulating androgen levels, which are adaptive for men for other reasons (muscle growth, aggression, etc.), also cause facial hair growth. There are many traits which might be adaptive which are not present because...they're not present. Night vision or canine olfaction would be useful for humans, but we are constrained by the history of our species. Our genome won't do that.

Why do most humans have have body hair around their genitalia and anus?

It also serves as a protective barrier to keep bacteria out of the genitals and anus.

Why do most humans have have body hair around their genitalia and anus?

That is a good question

Why do most humans have have body hair around their genitalia and anus?

Most women actually do have facial hair, but it is much finer, and almost invisible compared to mens facial hair. Men probably adapted with facial hair, as they spent much of the day in the fields back in the day, and the facial hair protected the face from windburn and sunburn. Women worked indoors more, so they did not need the protections. Now facial hair in men is more of a style thing. Genital hair is to help protect the sensitive skin of the genitalia, and also to keep things away (dirt, bacteria, etc.) from the genitalia.

Why do most humans have have body hair around their genitalia and anus?

so crabs have a place to live

Why do most humans have have body hair around their genitalia and anus?

I think that in design terms, the human bodies orifices are vulnerable to trespass by microscopic and also larger pests.

Perhaps then the hair down there acts as a physical barrier, like natural barbed wire, to prevent this "illegal" access.

Although some older women, particularly of certain races i.e. Mediterranean for one, DO tend to grow facial hair, it is more as a result than a purpose.

In other words men grow hair as a direct response to testosterone in their bodies and the changing hormonal balance occurring in some older women results in hair in the same way. It doesn't really do much; it is there as a response.