Obviously CEV isn't identical to preference utilitarianism, but CEV and preference utilitarianism have the following principles in common, which the hack exploits:

• Give people what they want, instead of what you think is good for them.
• If different people want different things, give each individual equal weight.

It seems clear that Eliezer got these ideas from preference utilitarianism, and they share some of the same flaws as a result.