The original comment seemed more belittling than frivolous. As for ego, I don't have a window into anyone else's psyche (do you?), but can think of an easy exp

The original comment seemed more belittling than frivolous. As for ego, I don't have a window into anyone else's psyche (do you?), but can think of an easy explanation that has nothing to do with ego: YC is a business. It would be irresponsible not to defend one's business against false or disparaging statements. Beyond that, it's important to hold the discourse to a certain standard; we have many examples of the pestilence that befalls online communities where this isn't actively done. (Your comment wouldn't raise an eyebrow in many of these places, but it was locally acidic.) IMO PG does a pretty good job of pushing back on this kind of thing while at the same time letting reasonable criticism have free rein. That's a hard balance to strike and not likely how a runaway ego would go about things.