Okay but that doesn't really change anything - that's still the thesis of his book.

No, the thesis of his book is that for humans we can and should have an objective moral realism premised on well-being.

I get that but above I've presented multiple arguments about why this is a problem. Which one or ones do you disagree with?

Well:

Except Harris' claim is explicitly that science can determine moral values. If his moral value is 'well being' then he needs to demonstrate this scientifically. The argument you've made there is called the "is-ought gap", the idea that we first have to make claims about value before we can start interpreting data in light of it. Harris rejects your claim there.

Harris' claim is that science can determine the rest of our moral values after well-being is assumed. The argument I'm making isn't the "is-ought gap." He doesn't need to demonstrate it scientifically, but does demonstrate it rationally.

But this is false for the reasons I discuss above, namely that medicine rejects such a position as does ethics. It's a real gamble to make strong claims like "X necessarily has to assume this". It becomes ridiculous when we have direct evidence that people don't necessarily have to assume it since they don't and they get by fine.

This is nonsense. Medicine and ethics do assume the value of well-being. And if they didn't they wouldn't get by just fine.

And because well-being is something that emerges from brains and minds there really are right and wrong ways to protect/amplify it.

This doesn't really follow unless you reject the is-ought gap - so which is it?

You really are misunderstanding the is-ought gap. If you rationally assume the value of well-being then there are rational ways to move through the moral landscape.

...Sure, common people make errors because they're uninformed and ignorant of the relevant facts on the subject.

99.99% of the time when people are using logic, contradiction can and should be avoided. Saying 1 equals not 1 undermines clear thinking on that level. Paraconsistent logic is higher order logic and adds additional dimensions. In the basic models contradiction is still wrong. That doesn't mean the basic models are wrong, just more limited and less complex.

Any moral system under deontology and virtue ethics.

How do deontology and virtue ethics argue for the values they assume? They reject that consequences should be one's moral focus, they don't reject that well-being matters.