Dcn Joseph, I've looked over that SiR document you posted, and I don't see Bp Photios or Abp Chrysostomos ever calling the SiR heretical. Our language is very cautious and irenic. Perhaps you prefer to read between the lines and think we believe they are graceless heretics. But you haven't found any official voice of ours that comes out and calls them heretics. With Vladimir Moss, as we noted he has been coming around to the idea that they are heretics, but hasn't himself said anything about their ecclesiological status (other than that they are schismatic) or possession of grace. That is the correct attitude from his point of view, since he does not believe he personally has the authority to anathematize or declare loss of grace, although he does have the duty to refrain from communion with heretics, whether before or after condemnation.
"The fourth concession is that they agree not to use in future the expression “ailing members of the Church” to refer to heretics (6.8). If only the Cyprianites had gone a little further and admitted that this expression was wrong, then they would have freed from themselves from the charge of ecclesiological heresy – a heresy that I have called “the heresy of ecclesiastical elitism”.[2]However, they claim that this teaching of theirs has been “misunderstood” (without explaining how they have been supposedly misunderstood), and promise to refrain from proclaiming it in future only “for the sake of peace”. Until they recognize that they must refrain from proclaiming, not only for the sake of peace, but also for the sake of the truth, without which no peace can be deep and lasting, we must conclude that their adherence to this heresy, though weaker than before, remains…"
The 46th Apostolic Canon, with the interpretation from the Rudder:
CANON XLVI
We order any Bishop, or Presbyter, that has accepted any heretics' Baptism, or sacrifice, to be deposed; for "what consonancy hath Christ with
Beliar? or what part hath the believer with an infidel?"
Interpretation
It behooves Orthodox Christians to shun heretics and the ceremonies
and rites of heretics. They, i.e., heretics, ought rather to be criticized and
admonished by Bishops and Presbyters, in the hope of their apprehending
and returning from their error. For this reason the present Canon prescribes
if any Bishop or Presbyter shall accept a heretic's Baptism as correct and
true, or any sacrifice offered by them, it is ordered that he be dropped.
For what agreement hath Christ with the Devil? or what portion hath the
believer with an unbeliever? Those who accept the doings of heretics either
themselves entertain similar views to theirs or at any rate they lack an
eagerness to free them from their misbelief. For how can those who acquiesce
in their religious ceremonies and rites criticize them with the view of
persuading them to give up their cacodoxical and erroneous heresy?
An excellent footnote to this is available in the translation, but I omit it here for the sake of brevity, as it is very long. It consists of a comprehensive survey of Church practice in receiving heretics into the Church, and also of the Fathers' opinions on grace inside and outside the Church. Nevertheless, as you can see, the canon refers not to manner of reception into the Church, but also one's personal attitude towards the mysteries of heretics. This attitude can be manifested in various ways, include how you receive heretics, but also how you speak to them and even whether you believe their mysteries are true and valid. Moreover, this canon is aimed at clergy only, and the penalty is deposition. It does not impose an anathema as you claimed.
