I see a lot of people getting hung up on the third violation that gave her a point penalty, with the rationale being that being called a thief wasn't enough. In isolation, sure, I can see that.
This wasn't, however, in isolation, and Serena had been getting in the umpire's face ever since the coaching penalty during changeovers and right before games, demanding an apology, saying how she didn't cheat, etc, and let's face it; there was no way it was going to end of Serena's own volition.
Should Ramos have done nothing and let the rant get longer than most productions of Hamilton? No. At some point, enough has to be enough because no player, Serena or not, should be permitted to keep going on and on and on and on and on and on and on.
(And on).
Should Ramos have given her a warning, saying that any more and she'd be assessed a game penalty? No, and he had no reason to. Serena had two violations, and that's about a clear cut warning as it gets that you miiiiggghhhht want to stop before a third's handed down.
Then she called him a thief, calling his ethics as an umpire into question, and boom goes the dynamite.