The funny thing is she only gets this way at the US Open slam. It's weird I haven't seen it (not to this extent), at the other slams.
In 2004 they were some horrendous line calls against Serena when she played Capriati at the US Open. The officials had to later apologise to her, it was pretty blatant. I don't know if that and subsequent incidents make her super uptight at this grand slam.
However last night, I was truly saddened that this great champion couldn't control herself during the match, and ruined the moment for Osaka.
She's right about double standards, but perhaps let it go and then say something after the match in the press conference about having the rules applied fairly across the board in both mens and womens tennis. That would have certainly been better.