Many things result in technology being developed. War, for example, creates vast amounts of technology (including rocket technology, satellite etc) , but that is not a good reason to engage in warfare.
That's not the same thing at all. The benefits of a destructive pursuit don't make it a more attractive thing to do. They're in opposition to the negatives of the original action. The side effects of a constructive pursuit do make it a more attractive thing to do because they are in addition to the already positive result of the original action.
I don't disagree! In fact I firmly believe that the ends never justifies the means.
But I wonder how many people would consider a major war to be beneficial if it lead to real fusion ie. limitless clean energy for the world, the end of energy poverty, of nuclear fission, and end of global warming.