Some girls just don't care. Others, feel they don't need to or maybe some feel its confidence about their personality it doesn't matter. It the same thing about anyone thats over weight and not trying to lose weight and continuing to eat junk. even though it affects their health. Some people are more confident than others and don't worry too much about their physical appearance. I would feel embarrassed if i was in her position, but thats just my personality - i'm not that confident to begin with.
In the first place, nobody likes to have hair in the face more than a man i am definitely sure.. Maybe a few exceptional. But those girls might have hormonal issues and they might need a treatment or maybe they are undergoing treatment and just waiting for results. At this point, shaving just leads to increasing the number and the thickness of facial hair.. It is the same for other places. And the thing is when you wax, you have to wait again until it grows and then wax. The process takes time and when you wait for the hair to grow, it looks ugly. For razors, they make hair extremely dark, thick and strong. I am sure she doesn't wanna have that manly look. And plus of she is happy and confident in hersel given that she has hormonal disease or not, then it doesn't matter my opinion or your wish that she shaves. just dont look at her if it bothers you.
Some girl in my school was like that because she couldn't shave or cut her hair for religious reasons. Some girls just don't care about it, and some school girls parents don't let them.