No, I mean to argue that the existence of Newton's equations is completely uncorrelated with whether Newton experienced any qualia

You misunderstood my argument. I wasn't talking about qualia when I talked about Newton, I was talking about gravity, another phenomenon. Newton was affected by gravity -- this was highly correlated with the fact he talked about gravity. We talk about qualia -- this is therefore evidence in favour of us being affected by qualia.

How do they determine that humans "actually experience" qualia, rather than humans simulating the results of experience of qualia as a result of evolution?

What would be the evolutionary benefit of simulating the results of experience of qualia, in a world where nobody experiences qualia for real? That's like an alien parrot simulating the voice of a human in a planet where there exist no humans. Highly unlikely to be stumbled upon coincidentally by evolution.

The Occam's Razor result that "they act in a manner consistent with having qualia, therefore they probably experience qualia, therefore they are probably conscious" is immediately displaced by the Occam's Razor result that "they act in a manner consistent with being conscious, therefore they probably are conscious". The qualia aren't necessary, and therefore drop out of the axiomization of a theory of consciousness.

What do you mean by "conscious"? Self-aware? Not sleeping or knocked out? These seem different and more complex constructs than qualia, who have the benefit of current seeming irreducability at some level (I might be able to reduce individidual color qualia to separate qualia of red/green/blue and brightness, but not further).