User blog comment:Kaido King of the Beasts/Chapter 863: Who's Afraid of the Big Bad Mom?/@comment-28966845-20170420135507/@comment-176.254.82.124-20170420143134

It's obvious, Katakuri saw Luffy smash the picture, he thought he'd stopped the event from happening. Little did he realise that Brook was disguised as Luffy and smashed the picture.