The "trans wars" have been a LOT more intense in the UK than in the US (and it's a total non-issue over here in Japan). I guess I noticed it early on because I've always enjoyed the Harry Potter books, and JK Rowling has been such a central public figure in the controversy. Plus I'm a big fan of (and former participant in) women's sports.

This US Supreme Court ruling (which is a clarification, not a change in the law) is a massive game-changer. In specifying that older legislation, when using the term "women," was referring to biological females (since the notion of socially-based gender as something separate from biological sex was either unheard-of or an obscure academic discussion, depending on how old the legislation was), this ruling opens the way for designating female only spaces, female-only sporting competition, and other situations in which differentiation is clearly based on biological differences between males and females. That is, situations in which not differentiating that way is unfair or even dangerous to females...

Transgender people lose no actual human rights because of this decision. They still can't be discriminated against on that bases in the workplace, in housing, in access to services, and so forth. If some male wants to think of themselves as a woman and dress accordingly or even seek medical treatments to make their body more feminine in superficial* appearance, I have no problem with that. Same for trans females who want to present as men (and who I'd like to point out are seldom so insistent on playing "look at me" in public...most just seem to want to be left alone). Thus ruling just allows governments and organizing bodies to differentiate according to biology, and that's as it should be.

*It will still be a male body, of course, regardless of how much "wetwork" they've had: biological sex remains immutable at the cellular level.