Well let's play devil's advocate...
Let's make fuel unhardened. In short, make it so you can literally depirve a base of fuel. 0%.
I mean that's accurate, right? Fuel tanks were exposed targets. In WW2, fuel tanks, refieneries, etc were all valid and soft targets (and sternly defended)
Then let's hear the outrage when one porker comes into countless fields and wipes out fuel tanks left and right.
But...the game has made it so that it can NOT go below 75%. And that makes sense.
But ammo bunkers were bunkers. Let's harden them up to that level.
Let me cast this in another light...if ammo bunkers were taken down by a horde of bomb totting bombers or JABOs...Ok, i see that working fine. When when a solo 30mm cannon bird swoops in a few passes, suceeds, then augers....and then rinse & repeat for the next base....yea...that's gaming the game and showing how seriously soft our strat system is.