From the perspective of a current CMU student: the Software Engineering Institute (SEI) here is the responsible party here. Note that they are separate from the main ("academic") school of CS. They are a federally-funded research and development center, essentially a computing-focused contractor and consultant for the DoD (see more here: http://www.sei.cmu.edu/about/organization/workingwithanFFRDC...).

So, in short, the people at the SEI sleep as well as the people at Raytheon or Lockheed Martin that build the drones, or the folks at Alcatel-Lucent who helped the NSA way back, or maybe even the guys way back at Los Alamos. It's not like some grad students or CS professor got strong-armed into doing this. It's literally their job to do this kind of work for the DoD and other government offices. While the ethics of this line of work are certainly up for debate, they knew exactly what they were getting into.