I don't believe the argument is whether or not austerity is or isn't a good thing. The real debate is not 'if', but 'when'. Keynesian economics suggests that you reduce your deficit during times of growth, not during a contraction. Home finance analogies fall short in the fact that there is no analogy for a Central Bank. Of course financing debt should become a drag on growth, but the question is 'how much?', and knowing that, you can plan the best move to get out of a contraction. Too much stimulus and you create unnecessary future obligations, too much austerity, and you wallow in a sluggish economy for unnecessarily long. That's why the exact numbers here matter, and why a difference of -0.1 and +2.2 for a 90% GDP of debt is quite important.