I am American and I am British. I live in London. I lived in Alaska 47 years. I have heard generations of Americans tell the world 'what to do'. Even now, Mr Trump tells the world he would get other countries to listen to America when he's president. Sounds like many other Americans I know personally. 

Now, let President Obama call on one of its longest-standing allies to consider its potential for undoing one of the most critical treaty-projects of the post ww2 world (creating Europe as a supranational state) and people in the states criticize that?

I think some folks don't quite know what they're talking about here. The American president is right on this, actually, and a majority of Britons will listen to what he says -- and then, vote for that result they believe is best for Britain and Europe.