Pretty simple. They learned a valuable lesson last month in letting some plausible press reports on the course of future ECB policy action go unchallenged. Thus the market was initially very disappointed that the ECB did not unveil a fully formed bond-buying program at the August ECB meeting.
The ECB apparently could not let the idea of a cap on bond spreads go unchallenged lest the market once again prove unimpressed by what ever action the ECB decides to take at the September meeting. The ECB also took the unusual step of telling European politicians to STFU on monetary policy and stick to fiscal policy.
