Shielder is only a defensive counter to ranged. Ranged can still deal damage to everyone else and shielders that aren't facing them. You shut your own offensive abilities down while "countering". When in range you are then melee vs melee which counter each other depending on player skill and some stats. As long as you can manual block you can shit on players in melee with just a bit of power strike, and with the agi ranged usually have. During this melee fight, anything can happen. You get to the point where you can't push any more, you have more ranged shooting at you, other melee get involved etc
So its false to say that shielder is a counter. Its a defensive counter. A real counter to ranged would be something that offensively deals damage to ranged without much risk of taking damage themselves, and they would be able to deal this damage without fulfilling many conditions first, similarly to how ranged deal damage without taking damage themselves