There are orders of magnitude less submarine fire control techs than there are tank crew-members. I assure you, nobody "up the chain" who's deciding what does

There are orders of magnitude less submarine fire control techs than there are tank crew-members. I assure you, nobody "up the chain" who's deciding what does or doesn't go in a tank manual expects the material in it to remain secret more than temporarily. It's just not the kind of thing you can rely on when you're disseminating the document to thousands of people across hundreds of facilities. Basically they tell you boots to STFU. And then then they base the rest of their decisions on the reasonable assumption that given time some of you will fail at that. Classic "defense in depth".