Because if he looks up some of the things mentioned and did some research he would discover that his own facts and opinions are based on talking points and fluff. His opponent in this discussion is giving insight into actual facts and data that goes against those talking points and fluff. That does not mean one opinion is wrong or right, valid or not, it just means one participant is better informed. Rather than do the research and come back with a rational response, it seems easier to just go negative on the opposing side. No facts needed. We have deflection for these situations.