It seems to me that what can be kicked should depend on the PC's strength (and possibly class, regarding the ones capable of kicking down walls, etc).
Something like... if you kick an object heavier than 50*St, it won't move, and the weight above this value decides how much damage it does. This makes it so that you must have Strength of at least 20 to be capable of successfully kicking an anvil, and Moloch Armors are simply not going to move by kicking, no matter what. As for what happens if it's too heavy, I'd suggest something like Weight/50 - St damage, capped at, say, St. What this means is that, for instance, a character with Strength of 5 trying to kick an anvil (1000s), you work out the damage number, which is 1000/50 - 5 = 20 - 5 = 15... but the PC only has a strength of 5, which limits how hard they can kick, and thus it does 5 HP damage. A character with Strength of 99 trying to kick a Moloch Armor will be hurt by 15000/50 - 99 = 201, which is bigger than 99, and thus it does 99 HP damage. On the other hand, if a PC with 15 strength kicks an anvil, they are hit for 1000/50 - 15 = 5 HP.
I'd also suggest that kicking walls shouldn't be a fixed amount of damage, but should increase with strength to some degree (although I'd limit it somewhat, because you're not likely to be kicking a wall trying to get it to move, like with items). Something like Strength/4 (rounded down) would make sense. So if your PV is greater than St/4, you won't be harmed by kicking a wall.
Oh, and for kicking statues, a kick that fails to break the statue and that is strong enough to move an object of that weight should make the statue move, just like any other item.