In the military, you typically got one data set through one barrel length & weight with one load (possibly two different loads, depending on what you were issued), and not a lotta variation in sighting planes.
Very limited data, and the goal was not to hit a baseball at 100 yards using a 25-yard zero.
Military has the objective, for the average infantryman, of putting a bullet in a human torso out to 300 yards or so.
The 25-yard zero CAN achieve that & if that's all you want in terms of accuracy, go for it.
Remembering again that in the non-military world, there are so many variables in what the rest of us are shooting that the 25-yard zero simply is not the end goal in longer-range zero & accuracy.
Stating how the military does it really isn't very useful.
Different parameters, limited variables, limited data.
Denis