You are correct. YC emphasizes regularly that the forums are private and otherwise the people wouldn’t share as much or give blunter truth.
Having seen screenshots of the post in question, it was bad, but it also would have been strange to kick someone out for that. The poster is an asshole and proud of it, but the community seems to have responded directly.
The post specifically told others how to skip the line, which was lying about their profession to say they were one that was qualified but that then people on site couldn’t prove.
For further context, having seen the original post, there were also details on which questions made someone qualified and which answers were “unprovable”.
It was crystal clear what the intent was and the poster was called out for it. There was a strong negative reaction.
Having seen screenshots of the post in question, it was bad, but it also would have been strange to kick someone out for that. The poster is an asshole and proud of it, but the community seems to have responded directly.