the article's use of a made up term like "contagious sociopathy?" Sociopathy is a defined personality disorder. It is not contagious in the sense that someone else can "catch it" like the flu.
It's true that a sociopathic leader can promote sociopathic behavior, normalize it, and popularize it in society. A society that values and promotes that behavior can influence people's tolerance and imitation of it, creating a mob mentality. But using the term "contagious" with a professionally recognized disorder is misleading, creating the impression that there is such a recognized disorder.
I am not in the mental health field, but I have learned a little about personality disorders from psych classes. Some of the defining behavioral traits of sociopathy/psychopathy exist in everyone. There are degrees of the number and intensity of the traits, like a spectrum, for a genuine diagnosis of it. Some of the traits do show up more often among CEOs, politicians, and other leaders, but are not usually extensive enough in them to fit a mental health diagnosis. Of course, there are also some who would fit it if examined for it.
So, instead of a "contagion" of sociopathy spreading through society, it looks like what is happening is that some genuine sociopaths in politics are normalizing their behavior by manipulatively bringing out the worst in people. They are not turning people into sociopaths as if they had been bitten by a vampire. Instead, sociopathic leaders like Trump are adept at tapping into some similar traits that most people have and amplifying them with social acceptability.