If they are being called "fundamentally mental" because they interact by one set of rules with things that are mental and a different set of rules with things that are not mental, then it's not consistent with a reductionist worldview..

I deduce that the above case would be inconsistent with reductionism. And I think that it is logically incoherent, because I think non-reductionism is logically incoherent, because I think that reductionism is equivalent with the idea of a closed universe, which I think is logically necessary. You may disagree with any step in the chain of this reasoning.

What do you mean by mechanical?

I think you guessed: I meant that there is no division between the mental and physical/mechanical. Believing that a division is a priori possible is definitely non-reductionist. If that is what Eliezer is saying, then I agree with him.

To summarize, my argument is:

[logic --> closed universe --> reductionism --> no division between the mental and the physical/mechanical]