My guess about mentioning the race of his assailants is that so much has been made of the relationship between gay and AfAm communities in gay publications recently. Especially in the wake of Prop 8. It's been all over the blogs, the Village Voice and Out, and I've heard it casually mentioned in conversations between gay friends. I think it's one of the dominant issues in gay media right now. So race would matter within that context, but it's not a context that people who live outside of the gay community and who don't consume gay-focused media would be aware of. I don't think it was meant to be a dig at her race.
I have a few blogging friends who blog aggressively on gay rights issues, and one is a scholar of race and gender identity (and identifies as a black gay man), and they've been talking about this issue for quite awhile now. I think it's on a lot of people's minds in the GLBT community.