Two things jumped out at me. The first is that the PM had no substantive complaint and was basically being a bully. Some people do that. Since you had been r

Two things jumped out at me. The first is that the PM had no substantive complaint and was basically being a bully. Some people do that. Since you had been really interested in this job, you might have done the second thing, which is to take your complaint upstairs. I would have told the story to someone above the bully before resigning. They might have backed up the bully, to their discredit. But they might decided they can't afford the kind of turnover this a-hole creates. If this feels like going outside of channels, it is, but tech isn't big on channels in my experience. You might have saved an interesting job. At the least, it would have been an entertaining thing to do.