I... kind of think that discussing racism is hard and painful work, however you slice it. I don't think it's shameful to need to step back from it for a bit. There have been times that I've actually had to remind myself that it's all right to think about fun stuff and it's all right to have other interests.

On your more specific point, I think that the problem is when you go "this post is part of conversation X" and then produce something that isn't about racism at all. That I can see how people might view as derailing. Whether the solution is to make your post without mentioning the racism conversation at all, or to make it while acknowledging your tangent, I don't know. I can't see being inspired by ideas or discussing fandom as bad things in themselves. Perhaps it's lack of attribution that's the problem?

I think there will always be conversations about race, so "waiting until it's died down" may not really be possible.