What's Obama banging on about advising our youth not to withdraw from the world? How would leaving the EU be doing that? Leaving the EU will free us to do more trade with the rest of the world and if we lose trade with the EU (as they like to tell us) we'll have to make it up from elsewhere around the globe. I'd say that'd make us even more inclined to embrace the world, outside of Europe. Why would leaving the EU mean withdrawing from Europe? Does he think we'll stop going on holiday there or buying stuff from there?
Or is it just more scaremongering?