It's just a form of trolling and gaslighting. Trump never mentioned this treatment. Everyone who watched him speak of ultraviolet light and disinfectant yesterday knew what he was saying and suggesting. The stupidity of the words were readily apparent.

Yet, here we are, being told that we're all morons because it's obvious that this treatment is what he was talking about. Even though he never mentioned this treatment, and there's no reason to think that he was talking about this treatment in particular.

Edit: Trump is claiming today that the question was just "sarcasm"...