I'm a guy obsessed with women's fashion
What do you like about their fashion?
I like looking at pretty things, when it comes to women that's the only thing that matters
I see no problem here. Women have some pretty style choices, there is nothing wrong with liking it, even if you are a guy.
Women have good fashion, and I like fashion. That's all they are to me.
While it's great to have interests like fashion, it's inappropriate to reduce women down to something so simple. They're complex people, and should be valued as such.