The greatest fallacy of the pseudo-intelligent is comparing different first world countries to each other without considering demographics. It's a fallacy you have committed, along with everyone else who says "America is backwards lol". That is why it is a trope. It has nothing to do with American exceptionalism and everything to do with a relatively poor understanding of how we arrived here.
America is a punching bag for the rest of the first world because it has problems literally no other first world country has to face. Problems that are too innumerable to list here. Without considering the various reasons America is a Special Case (TM) in many ways, you're missing the greater point. Sure we could have a German tax system for the simplest filers. We got to the 1040EZ because we believe in theory governments should stay out of our business. Fundamentally this is a driver of the majority of the policies in America, and when viewed from the lens of other western countries it seems backwards because every country listed in comparison has a stronger, more involved, and (in my opinion) more dangerous government. Perhaps not dangerous now but given enough power and enough reason could become dangerous faster than America's current government system. In fact, the unparalleled level of power corporations in America have over things like tax law parallels the level of dangerous power governments have over their citizen's taxes elsewhere. It's an iteration on the same old process of control. Missing how they're the same it's simple to arrive at the conclusion America is the only "backwards" one. Usually this argument devolves into tax utility, which I won't get into here because that's a philosophical argument beyond the scope of the mocking of America that ALWAYS comes with this nonsense.