Whether one believes Joe Wilson's comment was appropriate, it is hardly unprecedented. As usual, the Democrats have done far worse. From Politico:
In 2004, Democrats delivered a “Chorus Of Boos” during Bush's Bush’s State Of The Union when he called for renewal of the Patriot Act., according to the Washington Times.
In 2005, Dems howled, hissed and shouted "No!" when Bush pushed for
Social Security reform in the SOU: "Foreshadowing the contentiousness
of the coming debate, Democrats broke decorum and booed twice,"
according to the National Journal.
At the time, CNN's Bill Schneider remarked, “It was unusual. I had never heard it at least at that level before. The Democrats clearly were booing, heckling, saying no when the president talked about the crisis in Social Security."
Yet, the MSM treats it as some kind of singular outrage, and some Democrats now seek to censor Wilson. This is typical fare -- a dog bites man story. If the MSM and the left Democrats were fair minded, that would be the man bites dog story.