Not huge on booing, but fans are paying to watch a competitive performance for 3 hours. McKenzie is an entertainer and like it or not he makes a lot of money doing it. If fans see a poor performance it’s their right to express their displeasure. Doesn’t matter if they know him personally or not. It comes with the territory and you can’t have thin skin. I personally would never comment on an athletes social media either, but that is the scourge on humanity that is social media in the first place .