1. On the issue of trans women supposedly dominating at sports, the obvious counterpoint is that the Olympics has allowed trans women to compete in women's sports since 1994, and there haven't been any sports dominated by trans Olympians. In fact, the only real effect thus far has been a bunch of legal wailing and technicality-running over whether or not women with intersex conditions should be subject to the same hormone limits as trans women. A sidebar which, ultimately, actually showed how little scientific evidence there actually was for any of it.
That's not quite right from what I can tell, the IOC only started allow trans athletes in 2004, not 1994. Secondly, focusing only on the Olympics isn't a good way to evaluate this. I don't think a lot of people are arguing that trans athletes are totally unbeatable, merely that they have an unfair advantage over the average competitor, and the Olympics, where the athletes are selected from the best in the world and are by no means average*, is the place that edge would be least likely to come into play. The Olympics also have actual rules and standards for trans athletes, whereas many other sports that allow them do not.
Third, there's very little scientific evidence for
any side of this, not just the anti-trans side, but what data does exist does suggest it is fairly plausible that trans athletes have an advantage (even wikipedia
admits as much, and wikipedia is hardly favorable to the right).
As for the wider topic of Terfs vs transwomen, while there are absolutely bad actors on the "terf" side, that's not what's happening in this specific case, and frankly I've seen the terf label thrown around to silence anyone that has any criticism of the trans movement whatsoever (J.K Rowling being the most famous example). That's an understable defensive reaction, but that doesn't mean it's always justified.
EDIT:
*IE, Michael Phelps was at the Olympics because he trained very hard for a very long time. He was also there because he's a sort of a
mutant fish man who just happened to have a bunch of traits that made him even better at swimming on top of his own drive to succeed. Presuming trans athletes do have an edge (which is entirely possible), that doesn't make them instant olympians, it puts them into the running with all the other Olympians that also have a biological advantage over the average competitor, and all things being equal, there are a lot more cis athletes than trans, so the odds of a trans athlete making the cut are low.