I seriously dislike this song.
Girls kissing girls = awesome.
Girls with boyfriends kissing anyone else of either gender = cheating = not-acceptable-to-be-glorifying.
Besides, human evolution taken into consideration [which I assume she would have to be implying, as religion tends to frown on such things] it's hardly "human nature". That doesn't even make sense.
Therefore: advancing acceptance of homo/bisexuality, awesome.
But those of alternative sexualities shouldn't automatically be represented as cheaters, and there are breaks in the logical.