I learned the game the hard way but this question always made me wonder.
I always thought it was due to bad experiences some had.
After some time I have known two handfuls of women in the biz and half of them had bad experiences and still choose to see AA men.
The other half is divided upon personal choice and having a Pimp making the choice for them.
There is no way of telling really.
Only research and time can tell. If the ladies you are interested in go back and forth seeing AA men then most likely they are indecisive or in between PIMPS.
If women put up NO AA MEN and stick to it, more then likely its just personal choice.
This BIZ / HOBBY is full of surprises and curve balls I could be wrong.