Why did Obama say something so stupid?

I keep meaning to post this. Earlier this week, there was an interview in the New Yorker in which President Obama claimed that Islamic anti-Semitism is a product of 'recent decades' (i.e. if only we got rid of Israel, the Muslims would love the Jews). That statement is factually incorrect.

“Obama reveals that he has no idea, or doesn’t want to give the
impression that he has any idea, about