It might have been Caster's choice to continue with it publicly, but I still think it's a very difficult way to grow up, find your way out of your old life by being good at sports, but have your identity in question all the time, by yourself and others. For any child or teen that will be difficult, and I can have sympathy for actions that were made later even if I agree that they were wrong.
I hope that it won't happen so much in the future now that testing for DSDs will be better worldwide, I hope, given increased knowledge now.
It is much more than just the levels of testosterone, but those additional benefits are driven by having the testosterone in the first place, which does come from having the specific gene normally on the Y chromosome. It's not just an extraordinary characteristic that a female has. Yes, all winning athletes will have extraordinary characteristics in some ways - genetic advantages - but not in ways that sports divides the competition into. That's the issue.
I don't know if there are ways of measuring how much male puberty has taken place, so that those with partial or complete androgen insensitivity could still compete. I think that some evidence has shown that they may still have advantages - even those with complete insensitivity - but I am not sure. It's those cases that I think are more of a grey area, and I would have sympathy with those who are unable to compete as a result (even though I suspect that might end up being the correct decision, if there are some advantages to having the gene, even with total insensitivity).