Your claim: I can give you the exact criteria by which they aren’t Christians. You have to serve the Jesus Christ that actually existed to be a Christian.
Alright. Quote Marcion and Valentinus explicitly rejecting that Christ actually existed. Do not use deliberately defamatory Orthodox historical accounts like “Against Heresies.” You are positively claim they are NOT Christians, so by your own standard, you must demonstrate this. If you cannot, you acknowledge that they are.