The operative phrase was "doesn't burn well", which is true. Diesel is almost inert unless it's either atomised, or heated until it starts to evaporate, or heated and put under pressure.
Notice that diesel engines don't have sparkplugs? They don't work. You can get a petrol engine running with diesel by priming it with regular petrol and then relying on the pressure of the cylinders to ignite the diesel once it's running, but it'll get pretty annoyed at you in short order and probably won't work after you've stopped it, mostly because it's not mixing enough air and not operating at a high enough pressure to fully ignite the diesel fuel - which is also, incidentally, why putting diesel in a petrol engine produces lots and lots and lots of lovely smoke so everyone can see what a numpty you've been.
The reason is, the fractions we generally call Diesel aren't particularly volatile. You can toss a match in the stuff and it'll go out. You can do the same with a puddle of regular unleaded tool but it's a lot more risky because of all the vapours hovering above it. To get it to become volatile enough to burn you have to warm it up until it starts to evaporate. A diesel engine relies on compression effect to heat the diesel until it vapourises and explodes. That's were the bang comes from.
Which isn't surprising when you remember that the diesel engine was originally invented to burn brewery waste...