In the same way I can separate the art from the artist, so can I separate an awful woman's personality from her hair and appreciate the latter aesthetically and sensually. Ann Coulter is the perfect example of this for me. She doesn't have long rapunzel hair, and her hair is currently shorter and less thick than it was a long while back. But I was really turned on by her hair when I was younger (especially the way she very frequently flaunted her hair and constantly played with it on TV), and I would even include her among the high-profile women whose hair played a role in making me aware of my hair fetish. Though I find her views and even personality to be very reprehensible.
However, it's a completely different issue irl. I could never be physically or emotionally intimate with someone with gorgeous long hair and a bad personality. The former gets me interest, the latter confirms whether I will sustain that interest.