That is fucked, I didn't know that was a thing.
It's telling that someone like you, a well informed, intelligent person, didn't know this was a thing. I also consider myself reasonably well informed, and I didn't know it was a thing until they had a bunch of coverage about it after the Sandy Hook shootings. This points to a vast media failure. In their attempts to not look like raging liberals, they fear even nudging the boat that is the NRA. Scientific inquiry isn't political when done properly. Fear of information is far worse than any gun law that could be passed. Censorship is the thing that offends me most in life.
At this point, I don't know that it is censorship as one might automatically think of it, but the effects of misdirection, and intentional obfuscation are the same. I can understand that people are interested in maintaining the status quo, but an unwillingness to change is hurting the U.S. (and other countries) on many fronts. If I had to choose the one thing that I am most offended by, I would have to say it's fear; it limits the possible at all levels and twists the elegant and the functional into something less, far too often.
It's not traditional censorship, in the sense that no one is explicitly telling them not to print something. But it is implicit censorship, in the sense that they won't run certain important stories for fear of a giant backlash. Implicit or explicit, it's still censorship, and it's still wrong.