The author (Paul Krugman) is trying to say both:
(i) The eurocrats are ignorant, as they believe all their actions are correct.
Even though Brussels and Berlin were wrong again and again about the economics — even though the austerity they imposed was every bit as economically disastrous as critics warned — they continued to act as if they knew all the answers, that any suffering along the way was, in effect, necessary punishment for past sins.
(ii) If Macron wins, it makes the eurocrats even more so - so is not necessarily good.
Which brings me back to the French election. We should be terrified at the possibility of a Le Pen victory. But we should also be worried that a Macron victory will be taken by Brussels and Berlin to mean that Brexit was an aberration, that European voters can always be intimidated into going along with what their betters say is necessary.
Whereas the second is the main message, as the last paragraph shows:
So let’s be clear: Even if the worst is avoided this Sunday, all the European elite will get is a time-limited chance to mend its ways.
Krugman in his column is a long-time critic of the European economic policies which mainly take the form of austerity.