Looks like the Priest took the last sentence and ran with it, unfortunately for him utterly out of context.
You are not only confused but disrespectful. The priest was exactly correct and perfectly in line with Orthodox teachings.
It says, "is not plain bread but bread united with divinity." It is exactly what the priest said and what I have said as well, because it goes on to discuss the exact same concepts we both mentioned. Just as Christ did, the compound now has "not one nature but two".
I don't know what you think is missing from this summary but it is all there for me. Likewise it all matches the discussion on the OCA site I posted the link for.
MM - this needs the context of the whole passage. "Two natures" - the humanity and divinity of Christ. "Not plain bread" - rather St. John repeats himself twice: "the bread itself and the wine are changed into God's body and blood ... bread of the table and the wine and water are supernaturally changed by the invocation and presence of the Holy Spirit into the body and blood of Christ".
Again, this is what transubstantiation is - the substance of bread is changed into the body of Christ, to which is permanently united by hypostatic union the divinity of God. Thus St. John: "... since it is man's custom to eat and to drink water and wine, He connected His divinity with these and made them His body and blood ..."
Contrariwise, the union of the divine Word to plain bread would imply a monstrous hypostatic union of deified bread, rather than a deified humanity under the accidents of bread. St. John Damascene again:
The bread and the wine are not merely figures of the body and blood of Christ (God forbid!) but the deified body of the Lord itself: for the Lord has said, "This is My body," not, this is a figure of My body: and "My blood," not, a figure of My blood.
The question is really very simple, and there are just five options:
A) The bread and wine remain bread and wine, but Christ gives spiritual grace through their reception.
B) The bread and wine remain bread and wine, but the divinity of Christ is hypostatically attached to these so that a spiritual communion is affected by the reception.
C) The bread and wine are changed in substance to the body and blood of Christ, to which is attached the divinity by hypostatic union via His human soul.
D) The bread and wine are changed in substance to the body and blood of Christ, but the divinity of the Word is no longer attached to them via His human soul, just body and blood are present, and nothing else.
E) The bread and wine are not changed in substance, but are mingled with the body and blood of Christ which become truly present by invocation, to which is attached the divinity by hypostatic union via His human soul.
I can't think of any other options (other than further mixtures of the above). (A) is the reformed doctrine. (B) is something monstrous, a deified inanimate object. (C) is transubstantiation as Catholics understand it. (D) implies the slaughter of Christ and a new death for Him. (E) is consubstantiation.
Please let me know which one seems right to you.