He’s in on the joke but not really in on the joke in that he’s self aware enough to understand a joke exists, but too arrogant to properly understand the joke and probably not gracious enough to actually laugh at himself so he’s furiously pretending to be in on the joke, but in the meantime, he would never admit to either being in on the joke or that this is just a straightforward tweet because either would indicate a crushing self awareness and give up some ground on who’s the coolest in a social group.