I don't see how the second sentence makes sense of the first. A perfectly rational actor would not do nothing; they would carry out the most reasonable action given the information available.
I think you may have a confused definition of what it means to be a rational actor. Being rational means making the optimal decision given the information available
Maybe I don't understand what you mean by "perfectly rational". I'm using the definition from the article: A perfectly calibrated individual will be right X% of the time about statements in which they are X% confident.
