Even somebody who is largely altruistic might then choose to develop the overall harmful technology. They might reason that the harm H will result no matter what they do, since if they refrain somebody else will develop the technology anyway; and given that total welfare cannot be affected, they might as well grab the benefit B for themselves and their nation. (“Unfortunately, there will soon be a device that will destroy the world. Fortunately, we got the grant to build it!”)
Wow
