I agree that they don't do it explicitly from a postmodernist perspective, but postmodernism has many different forms, which includes things like truth based on identity group perspectives instead of an objective reality.

And I do agree that Foucault's study of madness (and prisons) is good; I think the problem was that he began to apply the power dynamics of prison to too many different avenues of life. He saw power struggles as fundamental in too many different things, including places where love, competence, duty, or a desire for stability would better describe the motivations for those situations.

Granted, it was a different time period, and the marginalized groups he mentioned back then have made incredible strides since then (at least in America and Canada), especially gay people. I don't know if Foucault could have ever imaged gay marriage becoming legalized or nationwide pride parades or a full month dedicated to LGBT folks.