@aseriesofstillimages
I fully accept that sex is not a spectrum, in the sense that the vast majority of people have either ovaries or testes and their bodies develop sex characteristics that reflect that (and other biological features like height and muscle development are of course also significantly affected by which reproductive system they have).
Sex is not a spectrum - but for the reason that there is not a spectrum of gametes. There are exactly and only two. There is no third gamete or combo gamete or half'n'half gamete. Embryos do not gradually accumulate enough of the sex characteristics of one sex to then be considered male or female. They develop primary sex characteristics according to their sex - which is fixed at conception. DSD conditions are described as sex-specific because some affect only males, the others affect only females. This is what a PP was explaining upthread - 5-ARD does not affect females because the female sex development does not require the penis-forming DHT. It's a very sensitive and complicated subject, but has been well researched.
Pseudohermaphroditism (apparent mixture of sex organs in one person) occurs because, for example, the agent which drives development of a sex characteristic out of initially undifferentiated tissue also suppresses development of the opposite sex characteristic. So if instructions to make a male sex organ are not received, the instructions not to make the female organ are also not received. But because the fetus is male, the female organ is not functional.
So whether or not you are born with the full set of functioning sex organs that you should have, you are still either female or male - because you either developed along the Mullerian pathway as a producer of large gametes or along the Wolffian pathway as a producer of small gametes - even if your development has been disrupted or impaired.
Sex is the biological role played in sexual reproduction. Even in species where sex is determined by a different factor (in crocodiles, it is the temperature the egg is incubated at) or where the same individual can be sequentially male then female (clownfish) or where hermaphroditism exists (snails), the roles are still either production of small gametes or production of large gametes. Binary.
I hope the people with DSDs that you know have lovely lives. Whatever their appearance, however they present themselves, they are nevertheless the sex that they were conceived as. And sometimes, their sex will matter.