My 2 cents:
Osaka was the better player and deserved to win and Serena overreacted to the penalty.
Beyond that, after the match, there was a virtual “who’s who” of elite tennis players (Evert, both McEnroes, Roddick, King and many others) who were incredulous that the referee penalized Serena in a major championship for receiving coaching, which players agree goes on all the time; and also agreed that men get away with far worse than calling the referee a “thief”.
A number of players indicated that they had done far worse and received nothing more than a “soft” warning from a referee, advising them not to do it again or they would lose a point.
I have no idea why the referee in question felt as if he had to penalize Serena when her coach gestured with his hands that she should come to the net more. It seemed like a pretty innocuous gesture imo, and frankly, when Serena tried it, Osaka hammered several passing shots right by her. He could have issued a warning, and that might have been the end of it.
In baseball, basketball and football, I’ve seen countless coaches and players go off on umpires and officials, including the Little Italian guy, saying far worse things than Serena. In most instances, a good official will first ignore the comments, secondly warn the offender, and then, and only then, T them up, penalize them or send them to the showers.
IMO, the referee was wrong not to initially issue a warning either for the coaching infraction or Serena’s comment to him. Serena’s overreaction was also wrong - and, as we all know two wrongs ...