Both the wiki and the article are sourced.

I mean...it's the IOC decides acceptable hormone levels for their competitions? I assume they reached those levels based on what falls within normal standard deviations. And there are numerous committees dedicated to testing hormone levels. The sports integrity unit, in tennis. They do it to ensure fairness, and trans athletes comply to the same standards as the cis ones.

But Martina is talking about how huge of an advantage trans athlete's have, so naturally with that massive advantage, a trans athlete would dominate, no?

Even in your example, you're assuming a post transition Isner would wreck the woman's field, and there's simply no precedent to base that off of other than "gut instinct".

Current Isner would probably do well in the WTA, yeah, but if he had to go through everything involving in transitioning, he would not be the same player-objectively. He would still have his height, but a lot of other changes would happen in his body and he wouldn't be the same athlete, and there's no way to say definitively that even he would dominate.