Publicly questioning the official 9/11 story is a great way to be ridiculed. The media and other propaganda outlets have so effectively labelled anything contrary to the party line as "conspiracy theory", discrediting anyone who points out the hundreds and hundreds of holes in the official story. The only credible theory (taking a cold look at the facts that have come to light over the past 12 years) is that AT THE VERY LEAST the US Government knew about 9/11 in advance.
Maybe, with time, it will become more socially acceptable to openly wonder what really happened. And probably by that time, most people won't give a shit.