My read is that the primary cause of the bad experience is because of a perception that the interviewer made a joke about missing semicolon in the white board code.
The attribution of that being “asshole” seems typical for a young guy who was stressed in a technical interview. Especially there could be additional signaling in the interview process that is problematic to the interviewee.
But the whole post does not sound too bad to me.
My personal worst example is one guy who is asking what I did previously, and after each time I gave an overview of one project, that guy just said: that sounds very easy (that was in Chinese, we were doing the interview in Chinese over phone). And that guy is a msft researcher turned engineer. I was internally amused at his employer being clueless about the skill gaps between an engineer and a researcher.
To me the saddest part was that he basically is not able to present an interesting description of the prospect projects in his own team (apparently that's expected based on his reactions to my previous projects), nor appreciate my side of the story. That makes the time spent close to being meaningless for both of us.