I found it fascinating. Watching the car's crumple zones work (even at this tremendous energy level) is always something we can learn from. Sure they're designed to work at much less energy, but they worked somewhat, even @ 120. A speed they were clearly not designed to handle. 
Are/were they "morons?" I would say no, as scientists conduct experiments outside the typical performance parameters all the time. This is how we learn. It seemed to me that proper safety precautions were observed for this experiment, and I didn't notice anyone acting "stupidly."
While this test is unusual, I think there may be some value in it, providing total analysis is performed. I don't find it necessary to "test" all cars as this particular scenario rarely happens, but sacrificing a couple cars and maybe a truck (lorry) or 2 wouldn't be the end of the world either. 
Can you imagine testing a motorcycle @ 120 into a wall? Talk about messy!