There's a few reasons.
I like to take more time to get to know someone before deciding whether or not I want to date. Had a few bad relationships in my late teens, got cheated on, and that, among other fun life lessons, has left me wary of people to the point that many have difficultly getting to know me and could, at least initially, say I'm quite aloof. Moreover, I've just never known people who started dating the same week they met stick together for more than one to three months.
The second point being that most women, at least those where I live, just aren't worth the effort. Sometimes I find one who catches my interest, or I catch her's, but then learn that she just wants a guy to help cover debts, loves her dog(s) so much I'm left thinking about a certain song by Rusty Cage, wants an unpaid live-in therapist because she has some form of unresolved trauma, or that she's just plain fucking insane. Everyone brings baggage into a relationship, myself included, but there are limits and standards; I come to the Farms to gawk and laugh at retards, I do not need to live with one.
The biggest factor is that a relationship just isn't a major goal for me at the moment. While it would be nice to find someone who suits me and can handle my unusual personality, I have hobbies and other interests which keep me occupied and satisfied with life.