Nope, the thing is our genders/sexualities are complicated. We think there's rules, but all the rules are false - we just have norms, and peopel go outside those norms. So there's your expression of masculinity/femininity. I mean, there are straight women who wear jeans and t-shirts and don't like pink - that's a kind of masculine express, but they're very much into guys. Or there are men who behave and dress in a feminine manner while still being men who like women. Butch lesbians are just another way all these 'norms' get mixed up. You get women, who are attracted to women, but who prefer to dress and act in a masculine fashion.
Hell, I have a friend who is born male, identifies as female, but prefers to dress in a masculine fashion. So she KNOWS she is a woman and has had surgery.. but prefers jeans and t-shirts to makeup and dresses.