My original comment was:
I think the decision ultimately seems to be the right one but I nonetheless do retain sympathy for those athletes who always thought, with good reason, that they were girls/women. I feel deeply uncomfortable with labeling some of those people as "cheats".
That is not a blanket that covers each and every DSD and each and every person's experience of it.
Santhi Soundarajan is a good example of someone I feel a lot of sympathy towards - even though I also agree with the new rules that would exclude them from participating in women's sport.
In short - raised in extreme poverty in rural India, suffering from malnutrition at times, but went on to compete successfully as a mid distance runner. They failed a sex determination test after winning a silver medal at the Asia Games, had the medal stripped and, after the public humiliation, consumed poison in a failed suicide attempt.
Yes, people around the world are obviously aware of the existence of periods and puberty, but many may lack access to sex education or may feel culturally restrained from asking questions about their genitals or reproductive health. It's also not as if DSDs are the only or even most common cause of primary amenorrhea . Even ignoring congenital medical conditions, there's malnutrition and - in the case of athletes - athletic amenorrhea.
My level of sympathy will vary by case, is counter-weighted by my sympathy towards the women wrongly deprived of medals, and doesn't change my ultimate view (that they ought not be permitted to compete - save that I think the inclusion of males with CAIS is reasonable, fair and safe).
I remain disinclined to readily apply the "cheat" label, especially in a blanket manner.
And I do think it worth bearing in mind that the vast majority of athletes with DSD come from developing countries - so the "nobody in a developed country will fail to discover they have a DSD" line of argument is of only limited value.