Postmodernist scholars are obsessed with hermeneutics, the process of interpretation. Truth-claims, because they are constructions of language, are subject to endless reinterpretation and are incapable of any definite, fixed meanings. Thus, note the excruciating exegesis of common language that is accompanying the scandal. Telling someone to be evasive is not the same as telling them to lie. Postmodernists have learned how to make words mean anything they want.
Truth is an exercise of power.
Ultimately, what is accepted as being true for any culture is a function of power. Those who rule impose their constructions of reality on everyone else. Thus the postmodernists' aversion for books by wealthy white heterosexual males, which are nothing more than projections of an oppressive power structure. Thus the postmodernists' willingness to accept historical constructions by women, homosexuals, and racial minorities that cannot be supported by evidence, but which advance the political agenda of the marginalized and so become liberating alternative truths. This overt politicizing of truth means in practice that reason, evidence, and fact-finding can be set aside by simply exercising power over one's opponents.