Diesel - energy density
I recall that diesel has a fairly higher density for energy than gasoline, just as gasoline is of higher chemical energy content than a partly oxidized fuel like ethanol. I would hope that diesel, containing a higher energy content (and creating a higher CO2 output) would go farther, just like I expect gasoline to go farther than ethanol.
And as for being brainwashed, the only brainwashing that is happening is that expecting conventional motored (no energy recovery system), heavy vehicles, typical of the North America car market (nearly all >3000 lbs) to get much over 40 mpg, is goofy. Vehicles need to be lighter as well as more efficient. Efficiency comes in both the ability to get the most motion from the least fuel as well as the ability to recover some of the energy invested in motion for re-use like hybrids do to varying extents.
