Thought experiments with mind-copying effectively involve dramatically changing the agent's values, but don't emphasize this point, as if it's a minor consideration.

Morendil's comment made me realize that my example is directly analogous to your Counterfactual Mugging: in that thought experiment, Omega's coin flip splits you into two copies (in two different possible worlds), and like in my example, the rational thing to do, in human terms, is to sacrifice your own interests to help your copy. To me, this analogy indicates that it's not mind-copying that's causing the apparent value changes, but rather Bayesian updating.

Getting around this particular implementation, directly to preference represented by it, and so being rational in situations of mind-copying, is not something humans are wired to be able to do.

I tend to agree with you, but I note that Eliezer disagrees.