[ericb]

It's a fair point.

If you rephrase it as "a civilization that mastered interplanetary travel and can split the atom somehow keeps crashing on our planet" it makes me wonder.

What if bugs, suicidal or thrill-seeking pilots or overly confident bureaucracies remain a fixture in the next stages of life's evolution as well?

Or what if fixing those problems is harder than the technology?

[joezydeco]

Or, perhaps, that civilization is using found technology from UFOs that crashed on their planet and they haven't quite figured out where the brake pedal is, yet?