Any system is only as safe as user competance.
Any computer system is only as safe as the competence level of its user. Since about 90% of people are inept at their jobs, you can understand the problems with security. Yes, it is entirely possible to lock down a Windows system just as securely as a Linux, or Unix, box. However, this need for having the computer itself run everything on the CPU is a very bad method of achieving that security.
Any secure system needs to move critical systems like firewalls and routing off of the CPU entirely. IT consultants know that the more work the CPU does, for sound, video and other "control" type of systems, the less stable the OS is as you introduce a chain scenario. If everything hangs in a long string on a single chain that system is heading for a major catastrophe. Many consumer level PCs are designed this way to save costs. More reliable systems will diversify and break up that load and let the CPU organize and control the flow of data instead of trying to do all the work itself. That is what separates a real workstation or server from a regular personal computer. Just like any other human system, be it a city, a company, or any set of networked control systems, each part of the system needs to have hardened error checking and recovery routines, and a level of autonomy to "breathe" and deal with timing issues and errors. If you pin everything into one person, chip, or module, you only have to have one failure or lock up and you lose everything. I know the government is above that from their experience with submarine and missile control systems. I can assure everyone that the story of a drone running Windows is merely amusing media spin, and not accurate at all.
