Not really abnormal. Plenty of people enjoy porn that "contradicts" their sexualities. I think generally because it's the act they like watching, not really one they like participating in. Who knows, I'm not sure how sexual arousal works, but if someone can have a fetish for feet, then straight guys can like gay porn.
I consider myself pansexual but leaning heavily gay; straight porn weirds me out. I've tried reading yuri, and all I can muster up is a morbid sort of fascination, or, I'll be extremely into it and have no idea why, especially since my sexual attraction for women stops just at the waist. o_0;;;
I'm not sure if I like because I wish I could be in a queer relationship with a girl (I'd never be able to consider it heteronormative/straight), or just because it's an interesting look at sex from an angle I'm not overly familiar with. (Although I'm most likely to enjoy it and gag at the same time.) Some people just write well enough to make someone come buckets over a sex/gender pairing they normally wouldn't like, so. -shrug-