I dunno, in the video he seems pretty amused by it, although that could have just been a shock laugh. I don't believe that Pewdiepie is truly an anti-semite, but even in context that video doesn't exactly make him look good. I do agree that in the greater overall context of people insisting he's anti-semitic even though he isn't, to the point that he made jokes about it, that video makes a little more sense, but you can't expect everybody to be that educated about Pewdiepie lore.
Here's the thing, it's no more important if Pewdie's actually an anti semite or not than whether Milo's actually pro pederasty or not.
Here's what Milo had to say about his recent debacle.
"My own experiences as a victim led me to believe I could say anything I wanted to on this subject, no matter how outrageous. But I understand that my usual blend of British sarcasm, provocation and gallows humor might have come across as flippancy, a lack of care for other victims or, worse, 'advocacy.' I deeply regret that."
Yeah Milo, it's easy to say "I was only kidding" after the fact. I wonder how often that excuse is used in sexual or racial harassment lawsuits. I also wonder if he would have clarified that he was not being serious had he not lost his book deal and his CPAC gig. Guess we'll never know.
See-nobody actually gives a fuck if you're "Just Joking". It's not the get out of jail free card that will save your reputation. Plenty of four channers use that excuse when pumping out Nazi memes, trouble is a casual visitor can't tell the ones who are using it "ironically" from the ones who really want to purge the untersmench from the face of the Earth. Jokes can be just as, if not more offensive than sincere beliefs. The mere fact that you were being ironic or joking won't stop people judging you harshly.
As others have said, punching down "Jokes" that mock other people's pain at best show a complete disregard for those affected if not actual advocacy for bullying or bigotry. They'll still get you called an arsehole and cause people to not want to have anything to do with you.