That’s the one.
No one knows for sure why he was banned but the most credible theory is that:
(1) he knew too much about YC’s lack of support for Aaron Swartz (who was a Reddit cofounder, thus YC alum) and his reputation when the man was in federal crosshairs, and discrediting MOC was a preemptive strike of sorts.
(2) he pointed out the existence of algorithmic manipulations (slowban, rankban) before anyone knew those were a thing.
(3) he wrote some blog post in 2012 you can’t even find but that one of the YC partners thought was personally about him. I can’t verify this because I think the post was deleted years ago.
It could be all or any of those in some combination.