/u/THedman07 requested in another thread for us to ban questions on 9/11. I started a response that ended up longer than I thought, and because it's important for us as a community it is being posted here for visibility. My original response follows.

Can we get a ban on 9/11 conspiracy questions?

This is a tough one.

On the one hand, if we ban 9/11 questions altogether, that in itself is a form of censorship which is an accusation very loosely thrown at mods — even though we have no history of ever suppressing factual information or dissenting opinions. This is something we'd like to avoid at all costs because it would damage our reputation as an open forum and place of discussion.

In some instances, questions about the WTC collapse are asked in an innocuous (if misguided) way, as was the case here and more recently here. Technically they break the soapboxing rule, but it's very easy to tell whether a user is asking genuinely vs. posting 9/11 truther bait.

On the other hand, this particular subject can be offensive or traumatizing to some people, especially if they were impacted by the original event. For the rest of us, it's frustrating and annoying to deal with 9/11 truthers, as I and others did for nearly a week, 2 years ago.

However, I strongly feel that it's my job as an engineer to prevent the spread of false information, flawed logic, and fearmongering when it relates to an engineering topic — so I did my best at the time to engage the offending users in a way that was both professional, and educational for non-engineers.

In conclusion, no, we have not and will not ban 9/11 questions because banning them outright is a form of censorship, and because the best way to combat conspiracy theories and the spread of misinformation is through education, recognition, and by establishing rigorous engineering definitions so that these types of conspiracy theories can't gain any traction.

This is exactly how AskHistorians deals with Holocaust denialism:

Educate ourselves, educate others, and expose Holocaust Deniers as the racist, bigots and anti-Semites they are. There is a good reason Nazism is not socially acceptable as an ideology – and there is good reason it should stay that way. Because it is wrong in its very essence. The same way Holocaust Denial is wrong at its very core. Morally as well as simply factually.

In the same vein, by engaging conspiracy theorists and disproving their claims with demonstrable facts and engineering logic, they cannot push their agenda and misinformation onto the general public, who do not have the engineering knowledge or mindset to refute their nefarious claims. This is the best way to promote engineering and science while preventing conspiracy theorists from gaining any credibility.

Is it frustrating? Of course it is! But this is the price we have to pay for maintaining an open forum that prides itself on the discussion of all engineering topics — not only what we feel comfortable talking about.