My gut reaction when reading this topic heading was “Now that is wishful thinking!”
I don’t know the answer to this. I think everyone is an individual, so I don’t like generalizations. I know of only a few “presumably straight” women who have personally admitted to experimenting with other women. I think many women (including myself) go through life quite happily without experimenting with the same sex. I also sometimes suspect (and please, understand that it is just a hunch, I don’t really know anything) that we all like to think people are like us. Straight people often assume that everyone they meet is straight, (and they are often incorrect.) I wonder if sometimes gay/bi people perhaps do the same thing - by thinking that everyone (or all women - what have you) are gay or bi. Or, maybe it is just wishful thinking on some people’s part.