Blue most of your time you make stuff up

you can stack shields because the bone shield is stackable, but you can't stack stacks of bone shields? 
give me a break 
the real problem here is that there is one exception on the rules just for one card, it does not really make sense to me...
Its one shield card with 7 shields on it.
so it's a single card with "shield counters" on it...
i am deflagrating the card (which is 1 as you say) so it should go away with one shot...
Notice how this game is not magic.
I never said shield counters. I said a stack of 7 shields. Each shield is 1 permanent. The same logic is applied to pillars. You have a limit of permanent slots, but your pillars do not take up 1 slot each, the same is applied here.
Now as to the stacks not stacking, that is actually very simple. THEY DONT. Im not making anything up there, its just a fact of life
tm. Look at it like this. The general rule of shields is that UNLESS THE CARD SAYS OTHERWISE they do not stack.
Bone wall says that you can place 1 bone wall, and it "summons 7 bone shields that absorb damage from a single source."
Say you have 20 bone walls up right now. You play it, like any other shield, it replaces your current shield (which just so happens to be a bone wall)l and "summons 7 bone shields that absorb damage from a single source."
Theres nothing that defies logic about this card. It wouldnt make since if it DID stack 7 more onto each bone wall you play.