A theory about qualia is that they're epiphenomena, which I interpret to mean that causation goes only one way (from physical events to qualia), not both ways. I used to immediately reject that theory because we're physically discussing qualia. But then I speculatively proposed the neural argument above, and realized I was wrong. We only ever discuss the fact that we have qualia. We don't discuss the content of the qualia themselves. In fact it seems we can't discuss the raw experienced content of the qualia. So maybe they are very nearly epiphenomenal, with one niggling exception that the facts of their existence are apparently causally linked both directions (perhaps as explained by that putative neural mechanism).

Um, that might still be badly expressed, but it's my best effort. If it still doesn't work, then the whole idea is probably badly formed.

Perhaps a differently evolved or designed neural architecture could discuss the content of qualia. We might simply lack the wiring for it.