Originally Posted by moleymo:
“Perhaps Jemima sees people for themselves and not as a race, besides Gina isn't black”

I really think she is.
The OP poses an unexpectedly interesting question. Jemima was of course talking to Michael not Gina, but knew that Gina was listening. I don't think many people would state that they wouldn't date a black man, a) to someone they barely knew; and b) in the presence of a black woman. And when Gina asked "Why wouldn't you date a black man" it really was time to extricate herself gracefully from a possible hole, not to dig it 1000 times deeper by suggesting that of course a black woman would never (should never?) date a white man.
1. She dislikes Gina and said what she knew would piss her off; or
2. She genuinely does believe, in spite of being 41, that black people always date black people and white people date white (or 'dark' white) people; or
3. She was being a tiny bit Emily, and trying to sound rather cool and edgy and "let's be brave about this and say the kind of thing that most people wouldn't say".