The 70s was before my time, I remember the Canadian flag thing though. But as I understood that’s more about not wanting to be associated with other American tourists who can behave quite obnoxiously when traveling in groups and taking full advantage of strong cheap local beers and the lower legal drinking age. There is and always was some degree of anti-americanism from the left, but on a political level and not something you’d have to worry about as an individual tourist. The headline is also a bit misleading in that sense, this “anti-americanism” is directed at Trump’s shenanigans, not random tourists.