I share your amazement at these strange humans; they are as weird as naked mole rats! I began by being sorry for them and their inability to grow fur, except in odd places and on the top of their heads. Then I saw the males shaving their whisker pads and their female shaving hair under their armpits.
It dawned. They enjoy being hairless. They choose to be that way, poor deluded creatures. Mind you, their whiskers do not work like ours do: they can't move them forward and back or use them as an extra sensory tool. Still, why shave them off?
Now there is a human trend to shave the whole head. You just might be able to change your human's mind by climbing to the back of the sofa and giving him a vigorous grooming on his bare pate. But it probably won't work, as humans are difficult to train out of some of their weird behaviour.
We just have to content ourselves by laughing at these silly dumb animals.