Source: https://en.wikipedia.org/wiki/Conscription_in_Switzerland
You get your orders for your once a year repetition course about 3 months before, then show them to your HR department, who arranges for you to have paid time off, paid by the unemployment insurance or something. Then you go do it and come back to work. Your colleagues pick up your tasks while you are gone because you'll do the same for them later (and good teams value cross training anyway). Source: I was a team lead on a team with active Swiss army soldiers.
While you are doing exercises, you have access to all the normal army comms stuff, including presumably encrypted digital HF radio for voice and data, satellite days, VHF radios, etc.
This order is saying, "don't use commercial products, use the military comms systems we give you".
Kind of too bad they didn't give an exception for Signal though... :)
Especially if in response to some claimed attack on the public logs the company would say, "hah, hah, JK, the stream has been xor'd with /dev/random all along anyway".