Sure, the subset of people mentioning any trait is more likely to want that trait than the subset who doesn't mention it. But that doesn't mean the individual is accurately self evaluating what they want, especially when it comes to intangible things like open-mindedness. I assume preferenced on physical/tangible traits are more consistent between stated preference and reality.
Agree. Most obvious example being people’s self evaluation of attractiveness relative to their evaluation of another person’s attractiveness. That said, pretty easy to tell if someone humble, pragmatic, etc — just by engaging them.