Like for example, Swyer syndrome is an XY DSD where the individual has a female phenotype (including uterus, fallopian tubes, and vagina) but complete gonadal dysgenesis. No ovaries or testes. Because of oestrogen deficiency, such individuals end up with a very high risk of bone defects including osteopenia and osteoporosis - which is not compatible with competitive sport.
Even with CAIS, an XY DSD where the body cannot process testosterone at all so despite presence of testes the individual develops an otherwise female phenotype, has a curiously higher incidence in athletes competing at an elite level, compared to the average within the general population: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5643412
> although they are likely to be taller than the average 46,XX woman given some height-determining genes on the Y chromosome and perhaps some that increase lean body mass. Mutation of this gene is found in fewer than 1 in 20,000 in the general population but is relatively common in elite female athletes [noted as 1/421 and 1/423 at the 1996 Atlanta Olympic Games].
The case of mosaicism you linked is fascinating but also incredibly rare, even more so than other DSDs. Also it almost certainly doesn't apply to these two boxers because it would have been picked up on the karyotyping, as it was in that paper.
I feel that the BBC article was quite enlightening on the topic of DSDs in general, but not so much on the impact of and presence of specific male DSDs in women's sport at an elite level. Sport provides a selection filter so these skew towards the subset that confer performance advantage. Like, 5-ARD has dominated entire podiums: in the Women's 800m of the 2016 Olympics, every medal was taken by a male.
That said, I see this as a policy failure more than anything. The IOC's policy fails women by not attempting to exclude male physical advantage at all, instead just going by whatever an athlete's identity documents say. They prioritise inclusion of male athletes in the women's category more than fairness and safety for female athletes.
This is in contrast with how they police their other eligibility criteria, like weight classes where this is verified at the event by weigh-ins. It's strict, too: an athlete was disqualified in this Olympics for being 100 grams over.
I believe the IBA's process, even though they prioritised the safety of their female athletes and fairness in competition, was also flawed. They should have taken the XY karyotype results as the start of their investigation instead of the end. Though, neither Khelif nor Lin pursued a case against the the IBA's decision at the CAS. Which says a lot too.