Why is it that some modern women think they can go down on a woman and not be gay?

[Emma]

Interesting question/story. I've never heard of this woman before being British, but I will search her now.

I am a hetrosexual female. I have kissed girls in clubs for example when I was in my late teens but this was more for fun and messing about, playing at being more liberal than I probably am than any actual sexual thrill. I would never have gone further, simply because while I think women are beautiful creatures and I can appreciate that beauty, I have never had a real sexual attraction to one.
However despite defining myself as straight, on the rare occasions I have ventured into the shadowy world of internet porn I tend to opt for girl-on-girl porn purely because I find the fakeness and complete disregard for what real women find pleasurable you see in straight porn utterly repelent and it leaves me cold. But as I said, lesbian action is simply a fantasy for me, not something I think I could go through in real life, and to do so should make one question their sexuality. But I don't think this means she has mental health problems, and 28 isn't an unacceptable age to still be single. No age is really.
Too much emphasis is placed on labelling ones sexuality, and this idea that to know your sexuality you have to rule everything out. I don't need to go down on a woman to know that I am hetro, or have anal to know I wouldn't enjoy it.