To be fair, that truck is highly modified by the owner. In stock form it would not be like that at all. Yes, it would consume double to maybe triple the fuel but it is a 3/4 ton truck. Stock emissions would likely be not too far off from the VW and the exhaust no more visible than the VW exhaust.
Diesels have for decades been "power rated" at the point where visible smoke appears in the exhaust. That visible smoke is unburned fuel, and it represents the point where the legendary efficiency of diesels goes literally "up in smoke." It has been known for all those decades that the power output of diesels can be increased by injecting more fuel, even though they become less efficient. It has also been known for all those decades that diesels are very "dirty" engines, emitting NOx, carbon particles (soot), and a wide variety of long-chain hydrocarbons with and without nitrogen and sulfur (now less sulfur because there is less in the fuel). According to my old diesel textbook, even formaldehyde has been detected in diesel exhaust, and my textbook dates well before electronic engine controls. Electronic controls do not change the basic chemistry and physics of the fuel burn.
By the way, those pickup trucks pictured above are NOT street legal. It is a violation of EPA rules and Federal law to modify the emission systems of road vehicles, and that includes loud mufflers on motorcycles. That the law is not enforced is a different matter altogether.
"All those decades" ago was a long time ago Charon, no point comparing modern diesels to those now. Modern diesels filter out 99.9% of particulate matter now, if you stick a probe in a diesel exhaust, the N0X won't even register, I read a case earlier where a government enforcement tried to fine an Ice cream van for leaving his engine idling to keep the ice cream cool. After having it tested, the emissions barely registered, and so the case was dropped. And don't forget, petrol engines have harmful emissions too, the Hydrocarbons from a petrol engine are considerably higher than a diesel, not to mention the carbon monoxide. There's very little difference nowadays, have a look at the 2 images below. One is from a Peugeot diesel, and the other is from a Dodge SRT.
You are free to believe whatever you like. So am I. Diesels are dirty engines, and so are gasoline engines. The problem with both is intermittent combustion. The engines remain dirty, no matter that decades have passed. The "clean" exhaust comes about from external treatments, such as diesel particulate filters, urea injection, catalytic converters,and so on. Exhaust gas recirculation reduces available oxygen in the engine, thus reducing combustion temperatures, NOx production, and efficiency. CO2 production is a direct function of the amount of fuel burned and cannot be reduced in any practical way. Again, believe what you like.