Nabokov, Wallace, and Eagleton get Fryed

I found myself agreeing with Polemical Introduction quite a bit, Frye’s arguments seemed fairly convincing (but then again, so does each new article we read) and I’m inclined to assume that they’re at least partially valid. However, I often found his arguments implying the invalidity of several other arguments we’ve read, and I’m still pondering this contradiction.
           Right of the bat, Frye argues that “a critic is a better judge of the value of a poem than its creator” (5) and that “the poet speaking as critic produces, not criticism, but documents to be examined by critics.” (6) Assuming he means these statements to be valid applied to all forms of art, not just poetry, (which it certainly seems like he does) what do they mean about David Foster Wallace’s critique of Blue Velvet, or even Nabokov’s “Good Readers and Good Writers”? Frye argues that the artist can only be an artist, so are these essays not valid works of criticism after all? This doesn’t seem right, to constrict Wallace and Nabokov to artists and only artists, but Frye argues that if we allow this, we are falling into the fallacy of “the conception of the critic as a parasite or jackal” and denying the critic “his own field of activity”(6). This is a conundrum that I’m not sure how to resolve, but I pose the challenge to you wise RE:-ers out there.
           Another contradiction I found was his early discussion of separating literary theory from theories from other fields. He criticizes what he dubs “determinisms in criticism” in which the critic attempts “not to find a conceptual framework for criticism within literature, but to attach criticism to one of a miscellany of frameworks outside it.” (6) This description seems to fit a trend I noticed in our Literary Theory readings, a trend that Krzys acknowledged as we first began. Throughout Literary Theory, Eagleton spouts a rather blatant Marxist viewpoint, and seems to tie whatever is happening in literary theory back to his own socio-political views. Consider:

      “Deprived of any proper place within the social movements which might actually have transformed industrial capitalism into a just society, the writer was increasingly…” (18)
      “’Deny to working-class children any common share in the immaterial, and presently they will grow into the men who demand with menaces a communism of the material.’ If the masses are not thrown a few novels, they may react by throwing up a few barricades.” (21)
     “Literature would rehearse the masses in the habits of pluralistic though and feeling, persuading them to acknowledge that more than one viewpoint than theirs existed – namely, that of their masters.” (22)
      “From the outset, in the work of ‘English’ pioneers like F.D. Maurice and Charles Kingsley, the emphasis was on solidarity between the social classes...” (23) 
      
          And that’s just in the first eight pages of the chapter. At first reading I considered these Marxist musings harmless add-ons, but how do they affect the overall effectiveness of Literary Theory? Frye insists that “Critical principles cannot be taken over ready-made from theology, philosophy, politics, science, or any combination of these.” In many parts of Literary Theory, Eagleton uses simultaneously occurring social and political movements as a crutch to explain the movements in literature, but is this valid? While Eagleton’s arguments often seem logical (Literature’s rise as an answer to the failure of religion? Sounds good to me), am I just falling into Eagleton’s trap? Does the history of Literary Theory naturally show these socio-political correlations, or has it been distorted and filtered to fit Eagleton’s views, and presented in a persuasive way? Since I don’t have a good grasp of Literary Theory outside what Eagleton has taught me, perhaps I cannot know the answer to this question until I read an objective history of literary theory, which surely Eagleton’s work is not.