You have to use an extremely expansive definition in order to reach 1%. So expansive that it renders the term meaningless.
That 1% number comes from the Fausto-Sterling survey which incorrectly lumps in Klinefelter syndrome, Turner syndrome, and late-onset adrenal hyperplasia. Eliminating those diseases yields a rate no higher than 0.018%, 2 orders of magnitude lower as the upper bound[1]. Only a small portion have cells for producing both types of gametes, only about 5% of all intersex people[2][3].
[1] https://pubmed.ncbi.nlm.nih.gov/12476264/
[2] https://medlineplus.gov/ency/article/001669.htm
[3] https://en.m.wikipedia.org/wiki/True_hermaphroditism#:~:text....
>broad hips, poor muscle tone and slower than usual muscle growth, reduced facial and body hair that starts growing later than usual, a small penis and testicles, and enlarged breasts (gynaecomastia)
It's by no means a settled matter what does or doesn't count as 'intersex'. I suspect that few reputable researchers would waste time engaging in such a pointless debate over terminology. Some relevant points in this article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5808814/
All that said, one can, if one wishes, cherry pick the smallest available estimate of the number of 'intersex' people and thereby dismiss the issues raised by these people on the grounds that they're small in number. I'm not sure how much scrutiny the logic of that rhetorical move would withstand.
My only point in responding is to add useful scientific/medical context. People can make what they want of that information.
Fundamentally I agree with what you seem to be getting at, taxonomy is hard.
It’s only informative if it’s true. With regard to the second conjunct, people with Klinefelter syndrome and Turner syndrome are typically functionally infertile.
I’m not convinced that ‘a lot of experts’ are even working on defining what counts as ‘interesex’. It would make more sense to listen to intersex people, who as far as I can see, tend to think that a fairly broad definition is useful.