There's one case I'm thinking of now where someone was as critical of YC (both the org and individual leaders) as anyone could possibly be, in a highly public and sustained way, and their startup later got funded by YC.
The article is about how YC defended one of its funded companies against a legal attack. It doesn’t say anything about YC refusing to fund someone who criticized it.
If you said something unflattering about YC once and got uninvited from demo day, that's on you. But being black listed from ever investing in any YC-backed startup even if you reach out to founders directly is taking things too far. And potentially an antitrust issue. Cabals are illegal, after all.
The only cases I know of where an investor was banished from Demo Day/YC’s network was for acting in bad faith towards founders. If YC banished investors who had a track record of being great to founders, they would be doing a disservice to founders, and therefore acting against YC’s own interests.
That aside, my original comment doesn’t contradict anything in the article (I can’t speak for the entire book - honestly when I tried reading it I couldn’t get past the first few pages).