Maybe being IN/OUT does not distinguish it but IMO the active choice does. As heresy comes from Greek to choose I would not describe as a heretic someone who was raised by parents outside the Church and they taught him heretical doctrines.
Ah, that's what you're getting at. Yes, I do not think that all heterodox (non-Orthodox of whatever confession) can rightly be described as heretics. From my reading, I do not think that was the belief of blessed Metropolitan Philaret of New York when he wrote about the salvation of the heterodox. A person can honestly hold to non-Orthodox beliefs because that is all he knows, but a heretic is one who rejects and fights against truth. In some cases, perhaps, the line between the two can be blurry.
At the start of the schism in the mid 11th century, the beginning of the papal reformation (a term used by non-partisan historians, but perhaps not by Roman Catholics), there was little difference, IMHO, between the post-schism Western confession of faith and that which existed in the same place prior to the schism. The theological apparatus which would come into place to defend papal supremacy and the filioque amongst other things, was established later, together with various innovations of liturgy and spirituality. So that, at the false council of Florence-Ferara, St. Mark of Ephesus could indeed term them as heretics.
I've always thought it sad that Roman Catholics have not, for their part, termed the Orthodox heretics. To us, IMHO, it makes it seem like the Roman Catholic Church will take a rather wide swath of belief and practice as long as there is some kind of acknowledgment of the Pope. Historically, in its Orthodox period before the schism, the Church of Rome was much, much less liberal.