In 1994 Mark Rosenberg the director of the National Center for Injury Prevention division of the National Centers for Disease Control wrote his desire to start a propaganda campaign to demonize guns and gunowners. He openly told the Washington Post that his goal was to create a public perception of gun ownership as something “dirty, deadly — and banned.”
Oddly, several CDC studies found significant defensive gun uses every year in the US, yet never published the results of those studies. So, besides their political bias, why didn't they publish the papers? Another factor, however, might have played a role in the decision of CDC personnel to not report the DGU findings. For CDC’s own surveys to generate high estimates of DGU prevalence was clearly not helpful to efforts to enact stricter controls over firearms, since it implies that some such measures might disarm people who otherwise would have been able to use a gun for self-protection.
This practice was stopped by Congress in 1997 through a statutory prohibition on the CDC’s use of federal funds to promote gun control. The provision in question does not actually ban research at the CDC on so-called "gun violence", it only prevents advocacy by the CDC for gun control. But Democrats argue that the provision has had a chilling effect on their propaganda.