I'm 90 percent sure he meant it ironically, or at least in an attempt to be a stupid edgelord. But it was still an unacceptable enough asshole thing to do that he deserves every bit of blowback he's gotten. Like trying to call a black person the N-word "ironically," no, you don't get a pass. You're just a different flavor of "bad person."

He's also retweeted Holocaust deniers. Could be a coincidence but that's would be enough for Elon to tweet "Someone should look into this".

Given his immediate actions the next day were to make a bunch of puns about how he "did Nazi the backlash coming" on twitter? It's much harder to give him the benefit of the doubt