The problem is that a huge swathe of mainstream and formerly mainstream macroeconomic viewpoints are classed as "Keynesian", and the mainstream "New Keynesian" macroeconomic model you speak of which focuses on manipulating inflation to overcome resistance to real wage cuts and assumes a minimal role for fiscal policy is rather different from the traditional "Keynesian" (and "Post Keynesian") emphasis on increasing net government spend to stimulate consumption in a downturn.
Pretty much any undergrad who's read their introduction to national accounts and Keynesian concept of aggregate demand and multipliers can devise a set of simultaneous equations which will yield both a real wage fall and an unemployment rise in a basic stylised macro model if you also slash G and raise T (especially if the assumption is - as with Greece - that the expected debt servicing will largely be repatriated to overseas bondholders)
Pretty much any undergrad who's read their introduction to national accounts and Keynesian concept of aggregate demand and multipliers can devise a set of simultaneous equations which will yield both a real wage fall and an unemployment rise in a basic stylised macro model if you also slash G and raise T (especially if the assumption is - as with Greece - that the expected debt servicing will largely be repatriated to overseas bondholders)