What should we make of the criticism of the ECB by the former central bankers?

In September 2019, several central bankers ( Ottmar Issing , Juergen Starck , Klaus Liebscher , Helmut Schlesinger, Hervé Hannoun and Nout Wellink ) published a manifesto that was very critical of the ECB. Their arguments were : "The ECB justifies its policy by the threat of deflation. However, there has never been any danger of a deflationary spiral ” ; " T he ECB protects heavily indebted governments from a rise in interest rates; the ECB has already entered the territory of monetary financing of government spending, which is strictly prohibited by the Treaty". What should we make of these arguments? There is actually no risk of deflation. This raises a question of transparency: the ECB continues to explain that it wants to restore inflation, while this is probably not its real objective. It is by buying government bonds against money creation that the ECB has restored euro-zone countries’ fiscal solvency and now prevented another public debt crisis by driving down long-term interest rates. The question is not whether it is allowed or not, it is what is most important: the advantage there is in having very low interest rates (fiscal solvency for all governments) or the drawbacks of very low interest rates (weakening of financial intermediaries, bubbles, capital outflows, taxation of savers). One cannot by principle reject, as the former central bankers are doing, a monetisation of public debt; one has to know, from an empirical viewpoint, whether what it provides (the disappearance of public debt crises) outweighs its costs.