My theory is that this is a very deep political metaphor propagated by the UK through a viral campaign to politely ask America to please be nice!
You see, the "big brother" in this presentation represents England (as is subtly hinted at by the "ENGLAND" t-shirt he's wearing). The baby (named Charlie - an obvious allusion to Charles Carroll, - 1737 to 1832 - delegate to the Continental Congress and later United States Senator for Maryland and the only Catholic signer of the Declaration of Independence), of course, represents "The States", biting ungratefully on the hand that feeds it.
England seems to be making claims that we're still dependent upon them for survival and eventual national maturation (and maybe we are, since we've signed away our entire country to into their power under a super secret legal agreement that goes back to Skull & Bones and all that mish-mash undercover stuff, but that's another blog). And even when poor England cries out in great agony, we bite down even harder, making poor little England cry. And what do we young, innocent but sadistic Americans do? We just laugh about it.
But England is a good sport and they simply politely inform us that our actions had repercussions that were less than desirable for them, thinking that they may appeal to our senses of compassion and feel some sort of regret. But we don't. We just laugh again and bite the blanket.
Sorry, Brits, but if you don't like having your finger bit, quit stickin' it in where it doesn't belong! (i.e. ALL UP IN OUR BIDNESS!)
YOO ESS AY! YOO ESS AY!