That example is to show how folks can decide something is "political" even if it's just something they don't like. That can apply to anyone, including people deciding if an advertisement is political or not.
Indirect propaganda schemes of your duck kind aren't effective. Some will be caught by the rule, some won't. So what? The rule still makes the media environment a lot cleaner.
Can you clean every last spec of dust from your driveway/sidewalk? Well, you don't have to, cleaning the big shit and mud is good enough.