You can't derive an 'ought' from an 'is'

Few debate that oneought to run quickly if their goal is to win a race. A tougher question may be whether one "morally ought" to want to win a race in the first place.

You can't derive an 'ought' from an 'is',  articulated by Scottish philosopher and historian,David Hume (1711–1776), Hume found that there seems to be a significant difference between descriptive statements (about what is) and prescriptive or normative 
statements (about what ought to be), 
and it is not obvious how we can get from making descriptive statements to prescriptive. means that
moral theories (ought) can not be deduced from 
factual knowledge (is).
Yet, as David Deutsch points out,  the growth of knowledge does not consist of 
finding ways to justify one's beliefs.
In the case of 9/11
The conspiracy theory (the US Government did it) is a factual 
misconception but it bears the imprint 
of a moral wrongness as clearly as a fossil
bears the imprint of ancient life.