This sort of thing is really the motivating example behind Newcomb's problem.

I'm not seeing the analogy. Can you explain?

The extortion attempt cost the aliens almost nothing, and would have given them a vacant solar system to move into if someone like Fred was in power, so it's rational for them to make the attempt almost regardless of the odds of succeeding. Nobody is reading anybody else's mind here, except the idiots who read their own minds and uploaded them to the Internet, and they don't seem to be making any of the choices.