I think the relationship between streamers and their audience is a more extreme form of the relationship between celebrities and their fans (some of whom may tend toward fanatical).
It's not surprising that things end up this way. When you remove the music/movies/whatever that the celebrity is producing and give the fans direct, real-time access to the celebrity's life things were bound to get weird.
One area where I disagree with the article is this characterization:
> [Viewers] are immersed in an online culture that believes that “social-justice warriors” and political correctness are the main obstacles to self-actualization
In my opinion this kind of "extreme speech" should rarely be taken literally. Instead, misogny/racism/xenophobia/ranting about "SJWs" on the internet should be viewed as a weird kind of performance art rather than an expression of genuine beliefs.
None of that makes it pleasant to an uninitiated spectator, but I'd compare that to how someone might find a dead baby joke terribly offensive. Really, I'd compare the whole thing to an inside joke between friends that would be considered "over the line" if someone else heard it. There's nothing new about that.