Turner is speaking, asking why the Gnostic thought was so subversive. He brings up the love/hatred relationship with Plotinus.
Plotinus loved how the Gnostics drew on Plato, but hated how they corrupted it with ideas of a bad Demiurge and corrupt matter.
Plotinus takes his wrath on the texts Allogenes and Zorostrianos. In Ennead 2.9, he accuses the Gnostics of violating Platonic metaphysics. Basically, Plotinus saw reality flowing from divinity, an unbroken chain, without mistakes.
The Gnostic, of course, saw a cosmic tragedy and many ruptures in reality.
Intellect to Soul to Matter, was to Plotinus, divinity always in three eternal phases.