I am actually wondering why friendship between "traditionally behaving" straight men and "butch" lesbians is not more common, after all, it should be easy to socialize with people who behave and think more similarly. I mean, friends are friends, and if you consider her to be "one of the boys", what's the problem?
It's only a problem if you have delusions of grandeur and actually believe that the storylines in your average porn would make sense, and you would be The Chosen One who converts her to at the very least bi, or with whom she (and usually her girlfriend, too) wants to experiment.