His true purpose is to punish the successful...and as much of America as he can!
I think his internal dream is not to ‘destroy’ America per se. Hillary, when asked if she loved America, said “I love the America that can be”. I think Obama has this same philosophy, only more radical. Hillary would like to create a socialist America ruled by an ‘enlightened oligarchy’ - with ‘democracy’ sort of like the Hugo Chavez version. She, like Obama, is a narcissist who wants a glorious legacy.
Obama, wants the US to survive as one of a bunch of United Nations nation states that are all ultimately beholding to ‘world government’. He's too blinded by his juvenile ideology to accept the fact that if not for the traditional capitalist US model much of the world would have suffered much worse than it has. We have given the world much, but we never hear that anymore. That's a topic for a different discussion, but my point is that he doesn't want to eradicate America, just ‘transform’ it into the America he can eventually love. He clearly does not love the one that has existed - the one that allowed him to go to private schools and to world recognized universities despite being, in his own words, a poor student.