Seriously? Again, read the post that you quoted.
They obviously do this to prevent people from stacking 100 potions and have them ready whenever th13 is released. They should set a reset rule once you upgrade your Th, i.e. number of items will be reset to its "allowed" limit if you have more than the ones "allowed" to store.
The problem with your argument is that there has been no change to when or how you can use your items. You simply cannot get more free items.
Consider this ... you walk to work every day and pass someone in the street that appears homeless. So every day you drop a dollar for them. One day you realize that they aren’t even using the money. They just keep collecting it and letting it build up. So you decide that you are no longer going to give them money until they use what they have. This does not give them any legal standing against you.
Any legal trouble could easily be thwarted by SC simply not making books and potions available by any means other than gems.
If we need to make space to store new rewards or magic items, in other words if supercell makes us selling these items or use them unwanted I expect to get a better price then the redicilous 10 gems for selling we get now....Or make it possible to store more items then we can now.
Why not a compromise?
Increase the amount of storable magic items and remove the overstocking?
There are many players who have maxed out buildings troops and defenseless I have a suggestion If you made the reward system for the clan games similar to the reward system of the war leagues Where a person would get a certain amount of let’s say clan medals they could use on whatever magic items they need and no one would have large amount of items that they will not use We all know that when I go to buy an item using gyms it cost alot but if I go to sell an item you only get 10 gyms There have been times when I could not collect from the clan games because my loot was full or I had to mini of a certain item If all of your builders are busy or you’re base is maxed out You do not have money to speed things up Then you lose out This is why some sort of the Currensy would be better for the clan games Then people can still collect and used the rewards how they need them Four instance if all of your troops are maxed then The power potion Is of no use To buy it cost a lot and gyms To sell you get only 10 this is why a currency system would be much better