This seems too uncharitable (I mean, "mostly" is kind of ambiguous in this context so it might be true, but...). I have plenty of complaints, and certainly things could be much better, but I think the rationalists in fact reward accuracy / high-quality reasoning much more than the surrounding community of bay area engineers, which itself rewards accuracy much more than US elite culture, which itself rewards accuracy much more than US culture more broadly.

For example, we do in fact put an unusual amount of stock on correct logical argument, sound probabilistic reasoning, and scientific inquiry, which do in fact tend to produce more accurate conclusions.