They succeed not by convincing you they are right, but by convincing you that knowing the truth is really impossible.

A phrase like "the normal conclusion" is itself propaganda, implying that anyone is abnormal who would have skepticism about whatever SideburnsOfDoom thinks; a thinly veiled shaming of, not even dissent, but mere neutrality and open-mindedness being faced with two parties offering conflicting narratives.

Imagine standing before a judge and saying, after he's heard the plaintiff's and defendant's cases, "Your honor, if you doubt the normal conclusion, it's likely that you have been swayed by propaganda."

Propaganda is everywhere, especially on the Internet. But of all the stories about which to imply that anyone who doesn't immediately choose sides against one party must have been propagandized--a legal dispute? Who's the biased one here?

See also https://en.wikipedia.org/wiki/Merchants_of_Doubt