[tel]

A rational person would consider the other direction to be more likely

You're, I think, making that conclusion based off the prevailing knowledge that ESP isn't true. A rational person seeking to learn if it is or isn't would still attempt to consider causality in the direction the op stated and otherwise be guilty of irrationality.

Some individuals will always experience slightly above or below mean (since variance isn't 0)

By my understanding of the standard ESP experiment the observation you state there would be evidence against the null hypothesis, evidence stating that there is some external factor tied to personal identity which changes your ability (for better or worse) to guess the identity of these cards. If the both experiment was perfectly designed and ESP totally impossible you'd expect that over time no one would have an edge on anyone else in their ability to guess these cards.

But people who have a belief tend to cherish and protect it

Much as you're doing now with the counterbelief?

(Disclaimer: I personally strongly don't believe in ESP. I also don't believe it's worth spending my own time on it. Finally, I do believe that if you're going to spend time on it you should do it carefully because it is clear that if there is an effect it's going to be something highly unexpected and subtle because most of the expectable and obvious things have been tested)