The OK sign joins a number of surprising symbols co-opted by the alt-right, such as the milk emoji, Pepe the frog and even, at one point, Taylor Swift.
Sometimes, trolls’ choices are far-fetched and innocuous – the milk emoji was appropriated because of the allegedly superior ability of white people to drink milk (large numbers of people in the rest of the world are lactose intolerant). But the transformation of mundane symbols into something to be feared is part of a broader aim to garner media attention, and getting one up on the people they think they’re fooling.
https://www.theguardian.com/world/2019/oct/03/ok-sign-gesture-emoji-rightwing-alt-right