If the ECB has the policy tools to return inflation to its objective, why does it not deploy them?

For the past decade, inflation outcomes in the eurozone have persistently undershot the objective of the European Central Bank.

Output and employment have been lower than they needed to be to deliver on the ECB’s self-defined measure of price stability. 

For almost all of this period of inflation undershoot, the ECB has set monetary policy while its own forecasts showed inflation would not reach its objective over the usual two to three-year horizon

Malcolm Barr, head of western European economics at JPMorgan, FT 22 July  2021

https://www.ft.com/content/a590671c-7c16-4767-b54f-c6ba592b6b4e