[jakkyboi]

They aren't re-anything as far as I can read. They concede this to say that sex does not mean gender or sexual orientation, to make the point that then by extension, those two categories are protected from discrimination based on preconceived notions of sex. In the case of someone being gay and fired for this reason, the discrimination lies in the fact that if a gay man was a woman, the employer would not have fired this person based on them being attracted to men. It's an extension, not reinterpretation.