What's the big scary secret?
There is no big scary secret. The only danger to worry about is that this community of schizo scifi nerds is going to have some perceptible and negative influence by spreading and popularizing their bullshit. Which will mainly be a problem for the computer science community, especially AI research, since those people are naturally susceptible to such infections.
But I am not too worried about that either. If all people who buy all this bullshit stop working on AI then maybe that will renovate the field and actually allow some real progress to take place by giving new ideas a chance and by introducing new perspectives which are less deluded by science fictional ideas. In a sense lesswrong/SIAI might function as a crackpot attractor, stripping out all negative elements so that actual progress can take place.
I endorse you not worrying about SI impeding AI progress on any significant scale.
I would also endorse, if you're genuinely interested in encouraging AI research, devoting more of your attention to the problems that are actually impeding AI progress.
Thank you for your cooperation and understanding. Don't worry, there won't be future posts like this, so you don't have to delete my LessWrong account, and anyway I could make another, and another.
But since you've dared to read this far:
Credibility. Should you maximize it, or minimize it? Have I made an error?
Discuss.
Don't be shallow, don't just consider the obvious points. Consider that I've thought about this for many, many hours, and that you don't have any privileged information. Whence our disagreement, if one exists?