She didn't complain in a coherent manner, she threatened the umpire (that he'd never be on another one of her courts, guess she's part owner now?), and, more to the point, it isn't the first time she's acted the fool at the US Open, (and has been assessed fines before), it isn't the first time she's acted the fool in other tournaments. She's just an a-hole.
Professional tennis players aren’t stupid.
They know the rules of the game.
They know how to play the rules to win to get paid and gain fame.
The entire affair was a con job by Serena.
From the responses of ESPN commentators, they were also in on it.
Spoke with a lot of pros today. They’re aware of it and really hate Serena.
Listening to Serena’s diatribe is like watching a tennis volley. She uses the discrimination shot, the same way she would place spin on the ball. She then tries to provoke the umpire by unilaterally stating the opposite of his call and warning, a cross court shot. She then accuses him of being a thief and a liar, a lob shot to provoke another penalty. It’s all a set-up to extort money from the deep pocket which has been awarding her millions on the circuit.