Why not? Where's the contradiction?

Well to start, the test, like observation in general, can never be "inaccurate". It simply is. The observation/test was either performed or it wasn't. The truth claim we'd be evaluating is "This test implies that the moon isn't made of cheese." If this is false, it implies that the moon actually is made of cheese, so your "system" basically boils down to "Any test implying the moon isn't made of cheese implies the moon is made of cheese." It's not even that it contains a contrdiction. It's just entirely based on one. It is a contradiction in its entirety.

If 99% of scientists believe that p, then that's very good evidence that p. Expert-consensus is prima facie evidence, right?

No. Scientists don't just divine a consensus and declare things to be true. They gather evidence. That's the only way the consensus is formed. Back in the day there was a "consensus" among "expert chemics" that alchemy was real and lead could be turned into gold. But that means nothing without evidence. Just like morality. Obviously all the objectivist philosophers would be in agreement that objectivism is correct, just like all the alchemists agreed alchemy was real.

Subjectivist philosophers are extremely, extremely rare; I don't know that I've ever met any of them.

Well you could start with Descartes. Then move on to Søren Kierkegaard. There are plenty. I wonder how you've missed them all.

Okay, how do you tell good from bad? 'Good' and 'bad' look like normative terms, and normativity is invisible empirically.

Your right. I should have said "Useful evidence is falsifiable." Unfalsifiable evidence is an oxymoron. There must be a way to know if the intuitions you're gaining from the evidence are true or not. Otherwise, by definition, it's not evidence. And for me personally, I think that it would be "bad" to pretend that non-evidence is evidence, primarily because I believe that holding false beliefs is "bad".

Um, do you really believe that? Smith hallucinates a pink elephant and (wrongly) comes to believe that a pink elephant exists. Where's the intuition?

He intuits that the pink elephant existing is the only way that he could observe them. His intuition fails to remind him that he could be a schizophrenic who hallucinates pink elephants. I thought that was obvious.

Okay, and why can't we do the same thing with intuition?

I mean, we can. The difference is that there will always be someone who disagrees with you, and if all either of you can say is "But my point of view is so obvious, look at all these people who agree with me," then there's no way to determine who's right except by simply asking more people. But then you're back to where you started. And what if there were 13 trillion aliens who all agreed humanity should be wiped out? Would they just automatically be in the moral right by consensus?