What did you expect him to do? Dump on the club in the press, and then leave and try to get another job?
He did exactly what every other classy professional would do: take full responsibility publicly, but be prepared to explain in details the real story behind close doors, when and if asked. He might have had that discussion when talking to Newcastle owners, but would not want it to be aired.
Whatever you think of Merrick as a coach, you can't say he is an inconsiderate fool.