With the end of the WW2, Heidegger is contemplating the devastation around him and he is looking for a reason. In doing so, he points at the essence of technology, subjectification, objectification, will to will, planning and obtaining everything in reach, and as usual - at the forgetfulness of Being. However, the end of the war is not going to solve the devastation and will decide nothing according to Heidegger; that is because the war itself is just a manifestation of our long ongoing metaphysical and rebellion uprising against Being.
One of the main topics in these three dialogues is the “will not to will” or “of letting go of things”. In Meister Eckhart's words: “where I will nothing for myself, there wills instead my God”. Against this “will not to will” stands the modern framing of men as the culmination of two thousand years of metaphysics; or in Nietzsche's words, the men who “would rather will nothingness than not to will”. Heidegger talks about evil, malice, and violence – identified as this “will to will” and as it stands together with forgetfulness, subjectivity, objectification, technology, and so on; evil that blocks us from going into nearness, waiting, and respectful intimacy with Being and beings. According to Heidegger, evil dwells in the essence of Being and conceals itself as “a secure state of the world, in order to hold out to the human a satisfactory standard of living as the highest goal of existence and to guarantee its realization”. In other words - the prosperity and welfare societies are seen by him as artificial and concealing worlds and as culminations of metaphysical devastation - and thus as evil.
It seems to me that Heidegger's goals here are: (1) to unsettle us, to break open, and to loosen up the metaphysical grip on us; (2) to teach us how to wait, to do nothing, to allow, to become who we are, to listen to the language and its call, to rest in the essence, to think, to give thanks, to be astonished, to search for the near and the simple, to turn back, to will not to will, to experience to open-region/Being; (3) and to open a path for us.