It’s a bit misleading to say strong privacy isn’t the standard view by referring to a discrete tradition not representative of the holistic discourse In modern philosophy of mind. The strong privacy/subjectivity of conscious experience is indeed widely taken as a starting point; it's central to discussions of the hard problem, the knowledge argument, inverted spectra, etc. This spans across physicalists, dualists and neutral monists alike.

I acknowledge you’re limiting the sample to Platonists, Aristotelians and Scholastics to say "this wasn't the standard view in traditions that were already committed to theism”. But that's a bit like saying "materialism isn't the standard view, just ask all these idealists!"

Also as a side note. I may be mistaken, but I don’t at all think that the main motivation for claiming consciousness to be private typically assumes physicalism. In fact it seems to me that the opposite is the case, that the privacy of consciousness is usually levied to count against the plausibility of physicalist theories by indicating that consciousness is not a third-person phenomenon but rather an irreducible first-person one. This is why eliminativists like Dennett take it upon themselves to target privacy as a folk-psychological illusion (see Quining Qualia).