If this is a matter of certain Faith, there will be a precise enumeration, not just one person’s opinion or another. It will be laid out categorically by some church authority besides yourself, and you should be able to find a reference. Otherwise, I will take your claim to be a bluff.
You should be able to back up your statement, especially since it is you putting your opinion to odds with genuine bishops and priests.
Why do you think that I take offense?

I regard the opinion that Orthodoxy is heretical as purely invincible ignorance. It is amusing to me more than anything, I enjoy these occasional discussions.
If anyone should be surprised that many Latin Catholics think Orthodox are heretical, it certainly would not be me. I’ve been around this block already.

I don’t care what you think of me, but I do care what the lurkers out there think of my church.
I state, Mr Dickerson, for the benefit of any lurkers out there, like the OP perhaps (as well as others) Holy Orthodoxy teaches nothing false, and also does not engage in novelties (which you accuse your own church of right here in this thread). It is this penchant for novel theological constructs and practices which is the most dangerous aspect of western Christianity (and must be carefully guarded against), and is also the rich inheritance of the Protestant communities, your western Christian progeny in faith. I don’t think the issue is nearly so neat as all that. A true heretic is one who invents doctrine either through an over-active imagination or cunning, preaches it as if true and imposes that upon others who cannot be expected to know any better. You are not important enough to be a heretic, nor I.
Those trusting souls who believe what they are taught are not even material heretics (to borrow a western Catholic term), but simply confused. Those who peddle the nonsense (whatever the motivation) are potentially soul killers, because the falsity of the belief might lead someone to act contrary to God’s Will for us.
I do maintain that many things taught by the Latin Catholic church would not be wrong if they existed in the realm of pious opinion, or theologumena. It is the imposition of these inventions, under threat of damnation, which is the sin.
Especially when these cannot be shown to be Christian teaching essential to salvation.
Analogous to the hierarchy of needs (see Maslow), there is a hierarchy of doctrine. A little reflection should make it clear that what one believes CAN affect how one acts, or regards the Divine.
The base beliefs must be correct, after which additional Apostolic knowledge can be discerned if it is available. This is a process which has completed long ago. What cannot be discerned with surety must remain in the realm of speculation, like the non-essential novelties which come into fashion and popular myth but fade again over time.
What your church has done most recently is to take a less important theological speculation (namely that a Christian must be under the theological supervision of the bishop of Rome no matter what to be saved) and turned it into an excuse to damn people. Because of this arrogance on the part of an office holder in the church, this theological opinion has trumped all other dogmas. It does not matter whether one believes in the Holy Trinity and worships properly. It does not matter whether one believes in the bodily incarnation of Christ, and it does not matter if one makes an regular examination of conscience and properly sincerely confesses, participates in the other sacraments or makes other notable personal sacrifices in Faith (even martyrdom!).
By trumping all of these (especially out of pride of office) the church has made this historically lessor, later and regional theologically minor pious opinion more important than any other teaching of the church, more important than the Ten Commandments of God, more important than any Gospel teaching of Christ himself. It negates them all. It stands Christian theology upon it’s head, completely inverting the hierarchy of dogma, the Apostolic and Gospel Faith.
The perpetration of this monstrosity is a very great sin indeed.
As Jesus did say: *"…But woe to you scribes and Pharisees…hypocrites! Because you shut the kingdom of heaven against men.
For you yourselves do not enter in; and those that are going in, you suffer not to enter!"
MTT 23:13
*