I’m not sure why Stewart is backing off here, but I suspect it’s because a lot of these older comedians are caught between the memory of actual censorship and the recognition that there are, in fact, problematic aspects of our culture that need to be called out. I don’t really get how you can lambaste Rowling and the Harry Potter franchise for antisemitic portrayals of goblins, even bringing receipts, wondering aloud how people could let that pass, then chastise news outlets for reporting that you did so as if they somehow took you out of context.
The only explanation, I think, is that Stewart, after having just defended Chappelle, doesn’t want to be lumped in with critics of Rowling, et al, who expect artists to be held accountable for their opinions and products. He realized that he accidentally almost got the point and had to backtrack. I’d have way more respect for him here if he’d just stick with it and say yeah, I think that was antisemitic, and as the creator of the HP series and that particular portrayal, I think it says something about Rowling, and I think she probably needs to address it. Instead, after making the critique, he backs off it and tries to separate the artist from the work in order to continue to try to reconcile his personal frustration with his larger worldview. I get that a big part of his Daily Show shtick was criticizing sensationalist media, but in this case, outlets were just reporting what you said, and I also think that Daily Show-era Stewart would probably tell current-era Stewart to have the guts to stand by his comments.