He doesn't believe there are hundreds of Fabrice Bellard clones who think working at your company wouldn't be a waste of their time. The myth might be that thinking about 10X is useful in any sense. You can't plan around one gracing you with their presence and you won't be able to retain them when they do.

Thinking about it personally, a 10X label means I'm supposedly the smartest person in the room and that I'm earning 1/10th what I should be. Both of those are huge negatives.