Actually, that's not the definition of a straw man fallacy. 

A straw man is an argument the other side never advanced. What I do above is apply the model to a simple instance it's supposed to explain and demonstrate how flimsy the model is. 

Here are more. Try it yourself and see if the White privilege model is robust enough to predict anything.  

Who is more disadvantaged? A white woman who was raised by a mother hooked on crack or a Hispanic man raised by a two-parent family of middle income means? 

How about this pair? A white man who is somewhere on the autistic spectrum or a man with Indian parents who goes to one of Canada's top elite private schools?

Or this one? A white girl with a thyroid problem that leads to obesity or a Black girl who is one of the top runners on her track team?

The WP model fails. Because it's absurdly simplistic.