I can't speak for anyone else, but it seems to me that the argument is somewhat different. I don't doubt that most working class Americans support their country's foreign policy (whatever it is, which seems far from certain to me). But I don't feel any need to agree with them. They are wrong. US foreign policy has been not just destructive, but the most destructive influence in world politics in the post Second World War era (and I don't exculpate Britain from that, the difference is merely one of scale).
Is it such a revelation that people on the left should take a different view from the majority of working class people? If we didn't, we would share their basically pro-capitalist point of view. All viewpoints begin as majority viewpoints. In the midst of Britain's war against Irish republicans, support for Ireland's self-determination was a lonely position. Nowadays, a majority in Britain favour Irish independence, and most understand that Britain's war was full of atrocities. If I had taken my cue from the given level of consciousness of British people during the war I would have been supporting the 'shoot-to-kill' policy.
-- James Heartfield