In case tptacek doesn’t respond, I’d like to give a (hopefully helpful) answer in the aggregate sense: many members of the information security industry refuse to work with the public sector (read: military and intelligence agencies) for reasons of personal ethics. They typically dislike the privacy-antagonistic ends to which they consider their skills, software or inventions would be used. This is particularly the case with many cryptographers, who could walk onto jobs or lucrative contracts with the NSA, but who would never even consider it.

I haven’t spoken to tptacek about this directly, so I want to make it clear I can’t elucidate his specific concerns. But the broad strokes of his principles are very common in the industry, and typically stem from a disagreement in how the government approaches security (philosophically speaking).