I have yet to see significant sexism/racism in open source, but I have seen an insurmountable amount of drama, bad behavior, prosecution and prejudice from people proclaiming to fight against it.
I believe it. I don't think it is a significant problem in OSS that we suddenly need behavior rules but there can still be instances of something like that occurring. The most convincing action was to not release details in my opinion.
I cannot imagine that this action is frivolous.