I'm attracted to the person, not to the label they paste upon themselves.
That said, if they're not interested in other guys, I don't pursue it, and it doesn't really matter that I find them attractive. I can have (and have had) male friends who are smokin' hot, and not go around trying to get into their pants. Because they're simply not interested in guys and I respect that. The same way I've had female friends who were smokin' hot, and didn't try to get into their pants because they weren't interested (either they were in relationships, I wasn't their type, or they were into women.)
Personally, I tend to prefer masculine men, but that's likely because I'm primarily oriented toward women. That said, there are limits. I don't really go in for the macho-shithead type, who constantly feels he has to prove his masculinity. But I don't confuse masculine with straight, as many guys apparently do. Some of the straightest guys I've ever met set off every 'gaydar' in the room, and some of the butchest men I've ever met were bottoms. Porn marketing strategies aside, one never can tell.
That said? I tend to get less shit about being bisexual from other bisexuals. There are a lot of monosexuals of either stripe who have a really massive investment in insisting that everyone who's ever even looked at another dick in a public bathroom is secretly gay and in denial. That shit gets really. really old, after a while.