Mostly his blanket dismissal that anyone who is not from his particular background could have anything meaningful to say about risk/statistics/trading. All academics are ivory tower intellectuals, all politicians are corrupt flunkies, everyone else not ruthlessly optimizing for optionality and/or skin in the game is stupid or incompetent or both.

What really ruined Antifragility for me was his apparent inability to make his point without insulting the intelligence of some central banker and/or professor literally every other paragraph.