Heehee. I'm straight, and the day I was able to go "Damn, that's a pretty man!" was a wonderful day. I realized it was the day I'd left all the insecure defensive homophobic bullshit from school behind.
It doesn't mean you're insecure in your sexuality. Quite the opposite, actually. It means you're able to say that without feeling confused or worried you're going to get beaten up. Straight women say it about other women all the time, anyway. If more straight guys are able to say similar, it's not that we're all turning bi-curious, it's just progress.