Oddly enough, I think the average GBer had above average intelligence (at least the ones that have been around for a whole) and I foubt many are truly racists. But this is an anonymous forum where people (white peoples) can express racial frustration.
Me for example, I don't consider myself racist at all. But I'll post the occasional chimp comment when I think it's funny or appropriate. But that's more directed to the chimps that black people hate too.