meta-ironic
When something is meta-irony or you're unable to tell if it's ironic or sincere.
4chan is incredibly meta-ironic, they claim that everything they say is a joke, but everyone knows they've radicalized people to committing hate crimes and race motivated killing. They might start out joking but eventually many of them end up believing everything they say and it becomes post-irony. However, some of the things that are said are so delusional you're not sure anyone believes them, so we can't tell if they're being ironic or sincere.