That's just your preference. There is no standard on what is attractive and what isn't. Some people only find supermodel bodies attractive, are they less straight than those that find average people attractive? There is no need to try to justify you finding women and men attractive. Whatever your preference doesn't change the fact.
But still there's some GENERAL standard as for what is attractive and what isn't, it has its source in biology. Though standards of beauty changed through the centuries, theer still are some general "rules" one needs to follow to be considered attractive (but for people with paraphilias which are rare). I know for some man a blonde headed woman will be more attractive than the red headed one or a brunette while for the other one a ginger will be the most attractive, the same is with the height or weight or a race for whom this woman belongs but still, those are just quite superficial layers of beauty while the core is somewhere else - none of them would find this woman beautiful if she had for example a big crooked nose and was obese.
A completely, 100% straight, woman wouldn't look at the other females in a sexual manner, regardless of their attractiveness. I find some animals attractive too (attractive in the sense beautiful not sexually arousing) but I'm not into zophilia.
I speak as no expert but media and society has made it acceptable for attractive women to be possibly sexually appealing to a woman or a man. Afterall, how many guys say they are turned off by two women kissing versus seeing two men kissing?
You sound heterosexual from your descriptions, even if "hot" women turn you on. You don't mention if you have sexual experience with women...but if not, then perhaps you are following the popular pornography portrayl of what women might be turned on by.
Hexi made a good point, where is the confusion? You know what you like...why think that it is confusing? Afterall, sexual attractiveness is just that...and being gay or straight is not a black or white phenomenon, it is more shades of gray from my understanding. Or perhaps like a scale from 1- 10.