I expect that Müller has been under a lot of pressure to say something.
But this statement will please no-one. It will not please the traditionalists, who wanted him to say something quite different. 
This is not a defence of Francis. In reality, it is yet another of Müller's suggestions that he (and not the Pope) is the ultimate 'custodian of the faith'. That he (and not the Pope) is the better judge of what is 'danger to the faith'. 
In his dreams, perhaps.
Perhaps it is his parting shot?