This is absolutely false, posted by a well-known troll. Vdub cut engine power during car tests to meet emissions standards, then cranked it up to 11 to make it "fun to drive". The real-world emissions were 10-40x above epa standards. This is the unethical, because it relies on fraud to make money sacrificing the environment.
Passenger car emission standards are g/mi and are the same for all fuel types. Epa is exploring ways to combat this type of fraud. But any test they make needs to be objective and reproducible for all vehicles, so it may be hard to eliminate this cheat vector.
My biggest fear is that the rep of all diesel vehicles will be tarnished. This isn't fair; both Mercedes and BMW make diesels that meet all emissions requirements and are fun to drive. Diesel vehicles are more fuel-efficient than gasoline vehicles and are definitely part of the fuel mix for a low carbon future.