if this means she should be considered a man for all purposes - and if not why not?
Not necessarily, because purposes are different. Sex in DSD individuals is not totally straightforward - that's why they're often called "intersex".
If you are assessing them for sports purposes, you care about overall body type.
But if you were trying to figure out how to approach fertility treatment, their physical build would not be the issue.
Surely at the heart of this debate is whether intersex people have the right to determine their own sex.
They have as much right as everyone to determine their sex, or indeed their height or their age. The trick is to actually effect the change.
If someone succeeded in changing sex, then obviously their body would change, and they would be assessed on their new body.
(This is getting a bit Monty Python. Men have the right to give birth - no-one's stopping them).
So if Semenya would get on and change to a female body to match their desired sports classification, we could save all the legal battles.