When Amazon develops facial recognition technology that can just as easily be thrown at migrants at the border the line isn't as easy as talking about building aircraft to fight fascism in Europe.
In liberal democracies there's a line between civilian technology and military technology, and you generally know what you sign up for. This is also precisely what the engineers here talk about, they did not join Microsoft to build weapons.
This isn't true. Consider Boeing, Colt, Texas Instruments, CamelBak, AM General. Even companies, like Colt, that are dedicated to making arms also sell products into the civilian market. That is in part because in a liberal democracy the government can not restrict a company to doing business solely with them: companies are allowed to recycle their know-how in the civilian market.
Working with private enterprise and repurposing civilian capabilities is how liberal democracies do defence. Should it be otherwise? It would seem to imply even greater scope for secrecy and mismanagement, and even less civilian control and input, if defence agencies didn't work with private enterprises for most of their needs.
How is it wise? Most weapons are developed and manufactured in a kind of public-private partnership.
During the Second World War, for example, the vast majority of industrial capacity turned towards building war equipment was private, dwarfing the capacity of government arsenals by a fair margin. Much of the design and development occurred in the context of public-private partnership, with national proving grounds and military agencies collaborating with aircraft manufacturers and other manufacturers of heavy equipment to design and develop weapons systems.
Boeing, Lockheed, Texas Instruments, Browning — and to go further afield, Supermarine, Marconi, Glock — these are all private names, not the names of government agencies. There are few cases of states where all, or even most, development of weapons systems is in state hands: totalitarian states.