Even though this is clearly a joke, I'm going to respond as if it were real. For the vast majority of women, lesbianism and bisexuality are a phase. Something that they experiment with when they are younger and then grow out of when they get older. In the eyes of most men, a woman being a lesbian in her past, or currently bisexual, doesn't taint her in any way.
Lesbian women aren't spreading sexually transmitted diseases (They are not exchanging semen, blood, or fecal matter). A bottom lesbian is still feminine. A top lesbian is forsaking her traditional role, by imitating a man's role in a relationship. But this takes a special kind of woman and is a bit badass. The lesbian top is taking on more work. Admirable.
That being said, your girlfriend is probably just a liberal. (Based on the flags she has.) Most women's politics are whatever they perceive to be the most dominant force in their lives. If liberalism is perceived by her to be dominant, then she'll be a liberal. If conservatism becomes more popular, then most women will shift towards that. Few women are able to go against what they believe is dominant. The exception is if she perceives her boyfriend/husband as being powerful. Then she'll unconsciously adopt whatever viewpoints he has and come up with rationalizations after the fact.
Women behave this way as an instinctual survival strategy. They don't have the physical strength of men and thus seek safety in numbers. Being a social outcast puts women in danger. So, they tend to go with what they perceive is the group consensus. If they are part of a group, they are more likely to receive the protection of the group. What most people don't realize, is that group consensus can be manipulated and faked.
