That quote seems silly. If there were hidden elements to 9/11 (or JFK, or anything) obvious enough for lone nuts to find, then it's reasonable to assume the government investigation would have found them also. Given that the government investigation didn't say anything about it, then, it's reasonable to assume it's because they have something to hide.
Since we're doing quotes:
Never attribute to malice that which can be adequately explained by stupidity.
-- Hanlon's Razor
Of course, once you start thinking in terms of stories instead of theories, it's easy to forget that only a tiny fraction of things that happen are the result of planning or motive.
(Since there didn't seem to be one for this month, and I just ran across a nice quote.)
A monthly thread for posting any interesting rationality-related quotes you've seen recently on the Internet, or had stored in your quotesfile for ages.