No, it's probably because it's a truck with a body-on-frame chassis instead of a unibody chassis like any modern vehicle, and was designed for towing and load-hauling rather than crash protection. If you want crash protection, you need to buy a vehicle with a modern chassis that was expressly designed for it. Same goes for the Expedition. And yes, handling could be a factor too: these vehicles have horrible handling and can't avoid accidents the way a good-handling vehicle can, and will frequently roll over.
And just try doing a panic turn (to avoid something) in a tall SUV and see what happens.
You can't just ignore the laws of physics. Center-of-gravity is an important thing.
http://www.consumerreports.org/cro/2012/02/rollover-101/inde...
http://www.iihs.org/iihs/topics/driver-death-rates
Compare the death rates of small, tiny, and midsize sedans (2011 data is the latest).
Then look at large SUVs. Huge difference. "All vehicles" = 28. Most of the large SUVs are single digits, most of the smaller cars are well above 28.
Curiously, Ford Expedition 2WD is above average and is an exception. I would love to understand why because it's a huge vehicle. The Ford Expedition 4WD is way at the other end, 5 deaths. Perhaps it has something to do with how people drive, or some flaw in how it handles.
Most trucks are pretty safe, but the Ford F-150 4WD has above average death rates, and is the most popular single model of pickup truck. I wonder if this is because lots of people buy this truck who don't really know how to drive a truck.
Anyway, some interesting data to explore there. Although as I pointed out, there are some outliers, in general the data lines up with the contention that larger vehicles are safer.