This is something I've been wondering all my life.

A previous poster said it well. Literally every other guy I've met in my life has had some degree of a hair fetish, but you'd only know if you took the chance and asked them (luckily I'm a nosey bastard so this doesn't really phase me).

I'm with Hoosier in that I prefer the "imprinting" explanation. I could tell you exactly why I love long hair, along with why I like it and all the experiences in my early life that caused me to like it so much.

It's hard thing to pin down, though. Here's a possibility though; notice that many other fetishes (breasts, feet, ass, body, etc.) are normally covered up in some way in public. Not so much with hair. I'm guessing we could talk about something like breasts sexually all the time in public because you only see them usually under something (like...clothes. sounds a bit odd to say but it's true). I think it would be weird to some to talk about hair sexually on a regular basis, especially around women, unless you were absolutely sure that both you and her/him were ok with it. It's something for men to notice, but not fantasize about.

Based on a very large number of conversation I've had with girls my age that did not have a hair fetish, hair somewhat relates to innocence childhood, and to sexualize it would destroy that image. Ever heard of the theory that when people under great stress they stroke their hair because it reminds them of their childhood/mothers doing the same thing? It's something like that. At the same time, many of the same girls told me that the majority of men they've been with have done or said things you would think only someone this a hair fetish would say (insist on growing out hair, hair pulling/sniffing on a regular basis, helping to maintain and constantly play with hair, etc.).

Seriously, it's an interesting question and something I've privately asked about (not directly, of course) all my life. This is all based on personal experience and quite a bit of awkward conversations.