The dude makes some really weird arguments.
"Payload": If you pull a 7K trailer, who cares what the payload is? Gas or diesel has you covered. If you have a 18K fiver are you really going to pull it with a gas truck because you're low on payload with a diesel?
"I can see my engine": LOL, ok, you can see your engine. "look I can change my plugs and plug coils because I can see them." Ya, so? Diesels don't have those so why worry about it? And if it's so important to see your engine why not just get an inline?
All in all that was a pretty weird video IMHO.