Obama personally doesn't really like Europe or Europeans that much.
He views them as mostly a continent of racism and dead culture. When you see how many European countries with burgeoning Neo Nazi movements, and ingrained cultural racism, you can't really blame him. He didn't even bother going to Paris after the Charlie Hebdo shootings, rightly so.
From the very beginning Obama wanted to reorient relations to South America and Asia. Even his big trade deal, pretty much leaves out Europe in the cold.
I can understand why Obama doesn't like Cameron, but it seems a little foolish of Obama to have destroyed a huge diplomatic advantage America had with Britain. Obama flushed that down the toilet, making Britain support China's own IMF, that would not have existed without British support.
And it has allowed China to legitimize many of their industries by going through Britain, like their massive Nuclear deal in Britain, that will bring money to China, and allow them to continue growing at the cost of American and European business. This is all because Obama diplomatically isolated Britain. Or one can view it as, Cameron isolating himself.
And this whole, we're being used for our military is ridiculous. No one forces America to fight wars, or have over 800 fucking military bases around the world, or have a military that is bigger than the next 13 combined together. Ever since WW1 America has been a war nation. America does this because it is in its own interest to do this.