Alberto Moreiras and others give sociological and political reasons for Arguedas’ huis-clos (see The Exhaustion of Difference and its notes). Priscilla Archibald (Imagining Modernity in the Andes) wants to depoliticize Arguedas’ suicide and I also think this is the more revealing view.
It is actually much easier to explain Vallejo’s depression in terms of sociological and political projects but I do not think it is necessary to go that far, even. I do not think he is either a depressive or caught in a contradictory project.
I think he just has a difficult life and sees difficult things, and feels sadness. Here is one of the brief biographies of Vallejo one can find; these are growing increasingly different.
I want to get Ricardo Silva-Santisteban’s 2010 biography of Vallejo although I am not sure it will be the book I want to read — the book I must write, I am guessing.