A white woman cannot add anything to misoginy ?
A gay man/woman cannot add anything to discrimination ?
Neither of these groups deal with the simultaneous quagmire that is racism and misogyny mixed together. In fact, there's probably more than enough articles and callouts out there about white feminism being exclusionary to women of color and white LGBT people co-opting black culture.
I myself am a black woman. But I'm also straight, and I don't feel this overwhelming need to step into LGBT spaces and make them about my plight or even assert my empathy. It's not about me, and the ills of black folks are not about white people.