It seems that the IMF's statement fails to take into account the many measures Greece didn't implement, namely pertaining to labor laws.
In the context of countries like Greece and Portugal, austerity just means that the governments can't spend more money than they earn, simply because they don't have access to it on international financial markets; the only money they have now is the Troika's. More money from the Troika means more debt, more interests to pay, and longer dependency on outside help.
Also, the main cause for the recession is that the governments want to correct the deficit by raising taxes, that is, by imposing austerity on their people, not on their spending. These countries avoid structural changes, which should target things like labor laws, the unsustainable Social State, the judicial systems, and create conditions to attract foreign investment.
I don't really understand how people can advocate for government stimuli in these countries when that's the sole reason they're in this mess to begin with.