Pepe the frog became associated with the online far right because it was a commonly used memetic avatar in general 4chan culture, and became intertwined with the space's shift to the political right in a fairly organic way. The association was boosted by (IIRC) the 2016 Clinton campaign's assertion that it was a far-right symbol, which was obviously embraced by those people as a sort of irreverent statement. Likewise, there may have been some very thin, actually existing connection between the far right and the "ok" gesture, but it really came about as an association that was imposed by the media and subsequently embraced by that community. To say these terms were "co-opted" isn't really correct.

I think there's actually a better case to be made that the pipeline of "co-option" (if you want to call it that) is stronger in the reverse direction. I posted a sister comment to yours about that.