I do think a lot of the problem is due to the fact our side blindly accepts the "born this way" BS that they came out of the womb attracted to other men's butts and can never change that fact.
I talked to some "open lesbian" the other day who had been loudly championing gay "rights" for all the years I've known her, now apparently she's fallen for some guy, gotten pregnant, has "gone through a lot of changes" and is "no longer gay". Of course she's pissed when I brought up the "born that way" BS and tried to talk to her about it. Civil rights, my @$$. You don't see black guys turn into asians one day.
Gay men might be a different story, evidence seems to point to a genetic factor (like there's a genetic factor for any number of mental diseases, I say so what) but facts seem to bare out that most lesbians go lesbian because they have been abused by men or are at worst actually bisexual.
Your pal may have always thought chicks were hot and figured she was a lesbian with peer pressure reinforcing this. She probably suppressed every natural attraction to a man she's ever had in order to fit in with her lesbian clique. Lesbians strongly hate women that play both sides of the fence because they all fear their GFs will leave them for a man.