If it was one racist dude at a conference I could accept it was a horrible oversight on the conference organizers part if they immediately apologized and assured it wouldn't happen again. But 8 racist dudes (or 12 if you count the more mask-on racists) is too many to be accidental or an oversight.
how is that not obvious
Well, probably some of them are deliberately racist HBD advocates, but are mask on enough to play dumb and hand wring and complain about free speech. Some of them have HBD sympathies but aren't quite outright advocates, so they don't condemn the inclusion of racists because of their own sympathies. Some of them are against HBD, but know being too direct and forceful and not framing everything in 8 layers of charity and good-faith assumptions isn't acceptable on the Lesswrong or EA forums so they don't just come out and say what they mean. And some of them actually buy all the rhetoric about charitably and free speech and act as useful idiots or a buffer to the others.
Roko is also violating their rules of assuming charitably and good faith about everything and going meta whenever possible. Because defending racists and racism is fine, as long as your tone is careful enough and you go up a layer of meta to avoid discussing the object level claims.