Being the kind of people who would do such things would have bad effects and sabotage friendly cooperation with the very AI folk whose cooperation is so important

My impression is that the bridges are mostly burned there. For years, the SIAI has been campaigning against other projects, in the hope of denying them mindshare and funding.

We have Yudkowsky saying: "And if Novamente should ever cross the finish line, we all die." and saying he will try to make various other AI projects "look merely stupid".

I expect the SIAI looks to most others in the field like a secretive competing organisation, who likes to use negative marketing techniques. Implying that your rivals will destroy the world is an old marketing trick that takes us back to the Daisy Ad. This is not necessarily the kind of organisation one would want to affiliate with.