Its easier than that. You can moderate by not allowing coments claiming something without proof or citation, and even more important not allowing personal attacks (unless they can clearly proof what they are saying about the other forum member is true).
The citations of Bruce's own words have been shown multiple times. What further proof would you like, exactly?
I have to say, if it wasn't for the fact that there is actual evidence behind these accusations, I'd be supporting the deletion argument right now. However, I also don't think this would have become an issue if there wasn't evidence, so the point is moot.
If it was not for a free and open discussion about an emerging crisis, this entire thing may have played out for months, causing massive damage to Bitcoin. Instead a rapid, focused, and determined investigation was conducted. It resulted in very serious allegations, most of which is accompanied by solid supporting evidence.
No, free speech and open lines of communication are absolutely essential in any crisis, and this is especially true for Bitcoin.