Thank you, Mr. Jeeves. Most men have no idea what fashion is all about, and I doubt that they would really want to.
I think the author's point isn't knowing about women's fashion, it is letting women know what men like. We wouldn't know a Jimmy Choo heel(had to look at the bottom of my wife's shoes to know that one) from an Ugg, but we know the former looks hot on a women, the latter looks like she stepped on a mouse.