>it’s really offensive to tell people with DSDs they aren’t their sex.

Not really true. Some people maybe.

>Sex is binary

Sex is complicated. Traits cluster bimodally, but it would be reductive, scientifically inaccurate, to say it’s a simple binary.

>People with DSDs are female or male

That depends on how female and male are categorized. The line between in the trait cluster and outside of the trait cluster is arbitrary. So it depends where you draw that line.