No, it isn't all about the skin-tight leather. Many men admire and are turned on by the tomboy, as well - that most often personified by loose overalls, gumboots, loose fitting shirts or tops, and etc.
Let's face it, all stereotyping is ignorant. Attractive bike, attractive car, attractie girl, attractive child, attractive man - I'll look and so will many others - doesn't make me a pervert, non heterosexual or anything else that some will seek to abuse. Just makes me 'normal' - whatever that is - but you know what I mean.