The OK Symbol? It was started by 4Chan AS A TROLL.

Its called Context. Even the ADL specifically mentions it in regards to the Iron Cross.

In the United States, however, the Iron Cross also became one of several Nazi-era symbols adopted by outlaw bikers, more to signify rebellion or to shock than for any white supremacist ideology. By the early 2000s, this other use of the Iron Cross had spread from bikers to skateboarders and many extreme sports enthusiasts and became part of the logo of several different companies producing equipment and clothing for this audience. Consequently, the use of the Iron Cross in a non-racist context has greatly proliferated in the United States, to the point that an Iron Cross in isolation (i.e., without a superimposed swastika or without other accompanying hate symbols) cannot be determined to be a hate symbol. Care must therefore be used to correctly interpret this symbol in whatever context in which it may be found.

Emphasis mine.