it seems like you're saying that work on the intersection between sexism and racism can only be used to discuss that same intersection

Oops, sorry - what I meant to say is that I think it's important to question to what extent you can re-apply that/any theory to something other than its original situation without changing to many of the factors that make it work. In Classics you might apply modern theory after modern theory to the ancient world, but you've always got to remember to put it through a filter, because otherwise you come to conclusions that are nonsense. Queer theory, for example, is a great way of looking at society, but the fact is neither the Greeks or the Romans had opposing constructs of homo- and heterosexuality, so you have to re-work a lot of the models. I'd agree with ithiliana about letting yourself frame your position as a reader.