Government already puts out information it deems "official". For politicians to start giving the impression of "endorsing" facts seems like the establishment circling the wagons. They would be saying, "There is no other point of view than this." Now think about that and how North Korea, China and Russia control their media. This would set a dangerous precedent and a slippery slope to Orwell and double-speak. The reason we have a vibrant political sphere is the free exchange of ideas, no matter how "interesting" they may turn out to be. You should be able to say what you want, without government suppression, as long as you are not calling on direct physical violence to someone/group. Otherwise you are instituting a form of thought control.