The word "rationalist" is misleading here.

In your example, it's true that a person would be unemployable because he has the kind of brain that leads to rational decision-making. However, it's false that this person would be unemployable because he made a rational decision (since he hasn't made a decision of any kind).

Therefore, as far as rational behavior is concerned, a rationalist getting hit by a meteor and a rationalist being penalized because of a fMRI exam are equivalent scenarios.

Besides, being rational isn't having a particular kind of brain, it's behaving in a particular way, even according to your own definition, "optimizing expected selfish utility". Optimizing is something that an agent does, it's not a passive property of his brain.