I've tried in vain to dissuade some people who've latched onto some of these "alternative" theories, not out of blind faith in the official story so much as to uphold the notion that if "They" can fake all of the evidence, so can the conspiracy theorists. Perhaps a cabal of government conspirators would have more to gain, but with the whole world available as an audience on the 'net, many of these other people don't need much motivation...

Let's not forget that the creators of "Loose Change" admit that
they started out making a fictional film based on a conspiracy theory. Just as it may come to light that "The Man" did the whole thing, it may come to light that these two filmmakers were just upping the ante to increase the impact of their film by claiming they stumbled onto "proof" that the official account was all lies.
I tend to think of Sherlock Holmes ("the simplest explanation is usually the correct one") when sifting through all of this stuff; a plot involving 4 teams of hijackers is the simplest explanation, whereas if you were to buy the other stories, you'd have to believe that the Twin Towers were rigged with charges months before the fact and the buildings were struck by unmanned radio-controlled airliners, the Pentagon was hit with a cruise missile for some reason (despite the fact that Washington is full of people who can tell the difference, even at 300+ knots), and some sort of bomb was used at Shanksville to create an inspirational myth of heroism. And, oh yes, all the registered aircraft were made to disappear, and their crews and passengers were coerced into hiding for the rest of their lives, or were all executed. That's a very complicated plot, and it apparently went off without a hitch. With every confidence that nobody would question any of it... even though many people have.
However, it's all food for thought... and the bottom line is that whoever did it, for whatever reason, it was a foul deed, and real people really did die (I knew some of them).