I feel like Bindel is conflating "born that way" as a non-discrimination instrument, in the way that an ethnic minority may use it, with that of a temporal clause to aetiology of sexual orientation. All the while hanging the concept of sexual orientation off of recent behavior and/or sociopolitics, and not physiologically-originated desire.

She does not want to give oxygen to the idea that the nature of her desire, and the nature of desire of other women who share the label are wildly different.