This is more about logic.
For this article to be relevant a spot for the Olympics of either gender has been taken by a trans athlete.
Which by conclusion means that a trans person outperformed the other gender.
Taking part in the Olympics is a difficult endeavor, for which you must qualify first.
That's a misleading way to talk about "outperforming". When the US brings over 200 people to the olympics, then if cis and trans athletes have exactly the same performance and without other bias you'd expect to see 1-2 trans US olympians every year just by chance. And you'd expect them to have the same medal rates as anyone else from the US. When someone asks if there's evidence of trans athletes outperforming cis athletes, that's not what they're asking for.