The article actually mentions 4chan, so you're not wrong. That's exactly where it comes from. As a troll, to screw with people who still haven't grasped "how the internet works". Lest people have forgotten about waterproof iPhones, microwaving your iPhone to charge it quickly, making "color crystals" (read: mustard gas), etc. It's a case of people having a laugh at people who really believe it's an alt-right thing. Although it may eventually become an "alt-right" thing. Poe's law and all that. But the thing about the "alt-right" is that they don't exactly try to hide it, most wear it as a badge of honor, and so don't need silly secret hand symbols to signal to one another... Don't forget that the Gay Pride flag is also a symbol of the "alt-right", so claims /pol/, the "gathering place" of the "alt-right".

Try to explain Bowsette to people who just "don't get internet culture". Internet culture has become a giant, collective in-joke that makes fun of people who aren't in on the joke. Think of it like someone who always pulls the chain of their gullible friend. Things like "Taurine is bull sperm, by the way." to mess with their naive friend drinking an energy drink. It's that kind of humor but on the scale of millions instead of single-digits/dozens. Ever get a group of friends in on a joke? Now imagine if millions of people you've never met or spoken to were in on the same joke.

I'm personally fascinated by internet culture - I "keep up" with it in the same way other people would keep up with celebrities. The ability for ideas to propagate across the network in the matter of days, sometimes hours, is nothing short of amazing.