Full Idea
Plato is liable to the charge of having been duped by a figure of speech, albeit the most profound of all, the trope of reification.
Gist of Idea
Plato's whole philosophy may be based on being duped by reification - a figure of speech
Source
comment on Plato (works [c.375 BCE]) by José A. Benardete - Metaphysics: the logical approach Ch.12
Book Reference
Benardete,José A.: 'Metaphysics: The Logical Approach' [OUP 1989], p.81
A Reaction
That might be a plausible account if his view was ridiculous, but given how many powerful friends Plato has, especially in the philosophy of mathematics, we should assume he was cleverer than that.