I understand what are you saying. But I dont see that. I think it has to do with the way I interpret rules.
I’m not a rules guru, and not sure if the meaning I give is the same. That interpretation sent me to a reductio ab absurdum, and thats what I wanted to show. At the same time, an exegesis of just a few rules, gives us some “valid” answers ( I didnt want to use those words either) that is precisely as almost everybody (at least you, Jim, and me) play it.
I think the ordenance/ft/dc exception is because its infantry that can fg, but dont have to (crew maning a gun / ft attack or thrown dc) but its only thinking of units that can fg, and as that, thats the only exception. A bmg dont need an exception because cant firegrup (either mandatory or voluntary).
Anyway, we will see an answer in a few days