I like the theory but alopecia has also attacked my fingernails, lashes that protect eyes from damage, nose hair that filters germs and collects condensation from my breathing (so my nose looks drippy often) and the worst of all delicate hairs in my ears that effects hearing. Don't get me wrong, I like how I look and for the most part I don't mind having alopecia, but I can't exactly call it highly evolved either. It's the little things that are a pain in the butt.
True enough! The nose hairs are evolutionarily useful. As for the hair in our ears, if you mean the "hair" inside the inner ear that is responsible for our sense of hearing, fortunately, those are not affected by Alopecia Areata. They are not true hairs, but are cilia. If Alopecia caused deafness and not just what is seen as "cosmetic" effects, I'll be there would be a cure by now.
Yes you are so right that they are not the same type of hair, and I don't know whether cilia is affected or not. I never really thought of lashes as the same type of hair either, and nails surely aren't. I think it's a mystery how this condition works, especially since its so different within each of us.