Yeesh, that was ugly. I felt absolutely terrible for Osaka. She played an incredible tournament, showed zero sign of nerves in her first major final, and most likely would have won anyway, only to have what should have been one of the best moments of her life stolen from her. Judging by her age and ability I don't think this is going to be her last win, so I really hope the next one ends better for her.
Regarding Serena, everyone seems to want to turn this into a hero or villain situation, but I dunno, is it possible to admit that she has very legitimate grievances with regard to how she's been treated by tennis establishment (and that most likely affects her perception of incidents like last night) AND that she also has a history of not reacting to losing all that well? Like, there's zero question that she's had to deal with a LOT of crap that no white and/or male player of her stature would have had to, and that there have been times when she's been genuinely treated unfairly (didn't the challenge system literally become a thing due to a match where she was repeatedly screwed over on line calls?). But also, I don't think it's a coincidence that these meltdowns always seem to happen in similar situations -- when she runs into a player who's white hot and she can't find an answer for their play, whether it be Clijsters, Stosur, or now Osaka. She's an icon and is rightfully lauded for many things, but she's also a person with flaws. Two things can be true.
When it comes to the chair umpire, I agree with a comment I saw that tennis officials desperately need to have some sort of get together to iron out just what is expected of them. Because while there's always some degree of interpretation involved in these things, right now there seems to be way to much that depends on the umpire's discretion. Yes, according to the rulebook all three of Serena's violations last night were justified, but I can understand why people would get upset when the whole situation unfolded in the same tournament where a different chair umpire literally climbed out of his chair to give a pep talk to a player. I do think some of the accusations being thrown at Carlos Ramos are unfair though, since people who follow tennis closely all seem to agree that he's known to be a stickler for the rules, and will basically call any infraction he sees regardless of who, when, or where. It was actually interesting that Serena's coach brought up Nadal in his interview, because I don't know about coaching violations but I'm almost certain that Ramos is one of the few umpires I've seen call Rafa on his (often egregious) time violations. Personally I'd prefer an strict, but consistently strict official to one who picks and chooses when to penalize infractions, which only leads to situations where players get used to getting away with things and feel like they're being treated unfairly when they actually get called on them (I've also never agreed with the idea of officials "playing to the score/situation" -- their job should be to enforce the rules, not decide when and where the rules apply). That being said, I also saw Michael Farber point out that the best officials tend to be the ones who are able to de-escalate tense situations rather than escalating them, and I don't think it would have hurt Ramos to have given Serena a soft warning before the third violation, even if it was just a reminder that the next one would cost her a game.