“”I, DOSITHEUS, by the mercy of God, Patriarch of the Holy City of Jerusalem and of all Palestine, declare and confess this to be the faith of the Eastern Church.”
Was he wrong? Infallible means unable to err. Did Patriarch Dositheos err in proclaiming the faith in 1672.”
He may well have been 100% correct, but that isn’t because he could or did infallibly declare anything and of course, as kawaii points out, a council could declare what he said to be heresy.
In general, Catholics view the indefectibility of the Church being such that such a profession would be protected from error seeing as it was widely adopted by the Church and presented to those outside the Church as a true confession of faith for them to adopt or continue in estrangement.
To claim that hundreds of years later a council could come along and say he erred formally in making this profession would be generally looked upon as being entirely contradictory to the promises of Christ to His Church - "behold I am with you always" and "the gates of hell shall not prevail against it", and the guidance given by the Holy Ghost to "lead you in all truth". If the Council could condemn, where was the guiadance of Christ and His Spirit for the 350 years that the Confession was held out as true?
No, Patriarch Dositheos is not in an of himself always infallible. But his profession is if it is widely adopted and held as entirely Orthodox for a long period of time.
Think of St. Vincent of Lerins dictum - "Now in the Catholic Church itself we take the greatest care to hold that which has been believed everywhere, always and by all. That is truly and properly 'Catholic,' as is shown by the very force and meaning of the word, which comprehends everything almost universally" - "quod ubique, quod semper, quod ab omnibus"
If Patriarch Dositheos confesses that which had been believed up until then "everywhere, always and by all" then his profession is fully Orthodox and also partakes of the infallibility that Christ promised His Church.