Yep. I don't think you quite understand how many women feel about their hair. Not being a man, I can't speak for all you men, but for many, many women, hair is a defining part of their self-expression. There's cultural, social associations you may not personally understand, but I assure you they exist.
I invest a ridiculous amount of time and money in my hair without a second thought because to me, it's part of me. Is it sensible? Maybe not. But it's going to continue. And for what it's worth, I always look tidy and professional in uniform.