"Am I correct in interpreting that the fix would the be the same as the functionality provided by RequestPolicy (which he mentions in the post)? I've used that for it for quite a while now, and although it works well for me as a power-user (who is concerned about security), I can't imagine the confusion and pain a user will feel despite the message suggested."

That was my interpretation as well and I reached the same conclusion. Having the average user make application-level security decisions is a very bad idea.

RequestPolicy is a wonderful extension and I think its use should be encouraged. But the average user does not understand enough about an application and how it interacts with third-party websites to make informed decisions about whether a particular interaction is good or not. False positives (where the user flags a good interaction) will lead to loss of functionality while false negatives (where the user fails to flag a bad interaction) will lead to security vulnerabilities that website owners can't prevent.