Funny, it’s kind of like the Trump accusation, somebody heard something second hand. I’m sure the Moscow Sretensky Monastery had no reason to fib.
It’s a serious accusation. If the Russians did invent this, it will come back on them. I am certain the EP would be (rightly) indignant at being slandered and will speedily deny the alleged remarks. He should have no difficulty getting corroborating witnesses.
The problem will be if he does not deny the comments.