Have you noticed how often those on the left assume an air of smug intellectual superiority? They believe themselves to be so smart and feel those on the right are not just wrong, but dumb, or worse. If they are confident of their arguments, why do they want to shut down or shout down opposing views?
This habit is brazenly prevalent at what used to be called institutions of higher learning. One student at Harvard went so far as to say that "academic justice," as defined by her, was more important than academic freedom and that certain research or speech not in line with her definition should be discouraged. There are other numerous examples where conservative speech at universities has been shouted down by those who feel it is not just their right, but duty, to deny free speech to those with whom they disagree.
Charles Krauthammer wrote a column for the Washington Post in which he pointed out the obvious inconsistencies between global warming theory and 30 years of climate records. Believers demanded that the Post not print the article. They say the "science is settled" and "the debate is over" despite the fact that their predictions have all gone bust. If their case really was rock solid, what are they afraid of?
The above are examples of a conscious effort to de-legitimize political dissent. There's a name for such efforts, it's called fascism. Our Founding Fathers would be appalled, as should all persons of goodwill.