There was no such assumption. My point was that you seem to be interpreting qualia in light of your monistic experience.

But frankly, I'm unclear on what exactly you're saying about qualia. Are you saying that our individual identities are illusions, so that the privacy of our subjective experience must be likewise illusory?

In that case, I'd say the concept of "illusion" presupposes the reality of qualia. An illusion is how something seems even if it's reality is otherwise. Talking about how something merely seems is the same as talking about qualia. This is just a redescription, not a refutation.