Just like everyone is doing austerity in 2010.

And if "doing stimulus" is how Germany got out of the crisis, countries that haven't still gotten out of the crisis should continue to do stimulus.

Nobody is claiming that the German debt brake caused anything before it was enacted. The claim is that the debt brake is strongly deflationary, which will only make growth more sluggish and debt more unsustainable in the future, and is therefore incredibly harebrained.

Keynesianism is intellectually hard, as evidenced by the inability of many trained economists to get it - Paul Krugman