Are extremely low interest rates really caused by insufficient growth and inflation rather than by ECB policy?

To fight deflationary pressures in the euro area, the ECB has been conducting exceptional policies, such as negative interest rates on excess reserves of banks on their accounts at the Eurosystem, or massive purchases of assets, essentially public bonds. The interest rate on the main refinancing operations is 0. Targeted long term refinancing operations are going to allow banks to borrow at potentially negative interest rates from the Eurosystem provided that they lend enough to the private sector. All these measures have pushed long term interest rates downward in the euro area. German public bonds yield negative returns for a whole set of maturities. Interest rates on saving accounts in German banks are extremely low. This policy of extremely low rates has been heavily criticized in Germany. The ECB is accused of exaggeratedly lowering the income of savers and retirees whose revenue partly depends on the return of accumulated wealth.