But then we all know what people's answers would be.

I think his the point is that if you took a Martian or Neptunian who happens to really hate Venusians and likes Neptunians in his native universe and presented him with a universe similar to the OP he would most likely not behave like a utilitarian he claims he is or wants to be. That's not really much of a problem.

The problem is that he is likely to come up with all sorts of silly rationalizations to cover up his true rejection.