If you take this incident to its extreme, the important question is what people are willing to do in future based on the argument "it could increase the chance of an AI going wrong..."?

That is not the argument that caused stuff to be deleted from Less Wrong! Nor is it true that leaving it visible would increase the chance of an AI going wrong. The only plausible scenario where information might be deleted on that basis is if someone posted designs or source code for an actual working AI, and in that case much more drastic action would be required.