I think it has to be with the stereotypes of what types of people tend to wear those items.
Fishnets are worn most by strippers, goth and punk girls. For the most part. There is a certain sex appeal to those different groups.
High heels is the same thing and mainly when it comes to things like stiletto heels. Think of all the "sexy" groups that wears these, strippers, models, most girls who by society definitions are attractive and "hot".
It is just a way of linking an object to person to confer that label.
By this girl wearing fishnets and stilettos, she is therefore hot and attractive.


