Yes when the cults find that the Bible doesn’t agree with what they teach then they always come up with this kind of conspiracy accusation that the Bible rewritten to disagree with them. I have seen this same argument from the Jehovah Witnesses and the Mormons and is their justification for rewriting the Bible to make a version of their own which better agrees with their teachings.
As far as I am concerned Platonist = Gnostic and a totally pagan non-Christian teachings, which various people in the church like Origen brought with them into the church to distort the teachings of Jesus and Paul. I am well aware of the syncretism of this period of the early church, where along with the Gnostics and the ideas of Plato, ideas from religions farther east like the Zoastrians and Hindus also inspired other distortions. And thus the early patriarchs had battle on their hand to keep the teachings of Paul and Jesus free of such distortions.