I believe the authors reading of the situation: its likely the interviewer wasn’t intentionally being cruel; most likely its this startups “unique thing that makes them stand out”; quirky twists that every startup attempts to make them stand out from the rest.
Honestly though, I think it ultimately worked out best for all parties. Its clear that the startup didn’t value someone that could be so vulnerable, and hopefully the author ultimately found a place that did.
My personal perspective is that for super early/founding engineer type roles you absolutely have to bring a greater part of yourself to work; you will be working over the weekends, working late, celebrating together and such… generally that environment is closer to a college club or fraternity than a corporation.