So you think that because there are vehicles in the world that are more polluting than automobiles that we shouldn't care about automobile emissions? Or are you saying that we shouldn't care about companies deliberately violating emissions regulations because there are other unregulated avenues of pollution? I honestly don't know what argument you are trying to make, but it feels like a massive red herring.

As a Chinese proverb once is alleged to have said, "No single drop of rain ever believes that it is responsible for the flood." No single vehicle is ultimately responsible for all of the pollution in the world. No ten vehicles (even cargo ships) are responsible for all of the pollution in the world. But that doesn't mean that we shouldn't make efforts to improve those things that we actually do have control over.

And here's a question for you: how old are you? Do you remember the late 1960s through the early 1980s when major cities were covered in smog, and acid rain was a huge environmental problem? I do, but a lot of people alive today are too young to remember those days, and the reason for that is that the clean air act has dramatically increased the air quality over major cities over the past few decades. Anyone old enough to remember what things used to be like knows that it works.

While we're at it, the issue with the VWs is the elevated NOx emissions. NOx leads to smog over major metro areas an asthma. Huge, ocean-going cargo ships aren't pumping out those emissions in major cities, or in populated areas at all.