I think the 'black comedy' post is probably closest. The Edward Woodward character is such a pompous ass. He's like Harold Bishop from Neighbours, or Alan Partridge. Plus the film is often funny, like the slapstick of him going round looking for the body (was it?) in cupboards etc. Not sure it's a coherent enough movie to be a successful allegory as polarised as suggested here. It's hardly Arturo Ui or Lohengrin.