That's what we're talking about. It's that kids game where you hold your hand like that, below your waist, and if your friend looks at it, you get to punch him. 4Chan started spreading stuff online about that being a white supremacist thing and the media gobbled it up hook, line, and sinker and now people think it is a racist thing and are getting in trouble over it. A lot of adults still play that game. Recently there was a team photo of a SWAT team and one of the guys was doing that hand signal and now he's of course taking heat for it.
4Chan has started other things that are just ridiculous, but there are dumb enough people in the world that they think it is real and start doing it for real. I think another thing they started was "Free Bleeding" where women don't use pad or tampons during their period and just bleed into their pants. It was all supposed to be a big joke until people started doing it.