I guess your theory is the same as what Alice Maz writes in the linked post. But I'm not at all convinced that that's a correct analysis of what Piper Harron is writing about. In the comments to Harron's post there are some more concrete examples of what she is talking about, which do indeed sound a bit like one-upping. I only know a couple of mathematicians, but from what I hear there are indeed lots of the social games even in math---it's not a pure preserve where only facts matter.

(And in general, I feel Maz' post seems a bit too saccharine, in so far as it seems to say that one-up-manship and status and posturing do not exist at all in the "nerd" culture, and it's all just people joyfully sharing gifts of factual information. I guess it can be useful as a first-order approximation to guide your own interactions; but it seems dangerously lossy to try to fit the narratives of other people (e.g., Harron) into that model.)