Free Speech after 9/11

I am taking a Global Studies class about the United States and the third world, we are reading a book called Tourists of History, the author claims that the American people do not see themselves connected to or apart of our history. For example, we only see the tragedy in history, like with 9/11, we don't see the events or actions of our government that would have caused such an attack. One of the chapters I just read was about the media response to 9/11, and how speech was 'censored' because everyone was being extra cautious not to offend or bring up memories of the attack. Companies pulled ads that had anything to do with crashing or attacks, TV shows or movies that had images of the twin towers were not shown, or postponed. The country was in shock, and the media seemed to be censoring their speech so as not to offend. I think this is interesting int he context of free speech, because it was like censorship, but it was not imposed, it was willingly done out of respect.