I'm not at a Combatant Command, but work in a smaller military operations center. KVMs are prolific because we frequently need to switch between computers on discrete networks with different classifications. For example: an unclassified network (with access to the World Wide Web, most common workstations for daily business), a US-only SECRET network, and 1-2 other US + $friendlycountry SECRET networks. You'll have 2 monitors and 2 keyboards at one workstation, each supporting 2 of the 4 networks. It's a mess.