Skyironsword said dim shield is OP. I said no, because his argument can work both ways. That's not agreeing.
Skyironsword had a claim. He supplied insufficient evidence to conclude his claim. You disagree with his claim. You used the same type of insufficient evidence to try to refute his claim.
Skyironsword:
Claim 1: Dim is OP
Evidence 1: A card can be OP even if it has counters.
OldTrees:
Evidence 1 does not imply Claim 1 is true
kimham8a:
Claim 2: Claim 1 is false
Evidence 2: A card can be UP even if it has counters.
OldTrees:
Evidence 2 neither implies Claim 2 is true nor does it refute any evidence Skyironsword provided. You did not address his logic.
You agreed that the evidence provided (the existance of counters does not imply the balance/imbalance state) was true.
You both made the mistake of using insufficient evidence.
The only thing you disagreed on was whether the card was OP or not.
Agreeing with someone's evidence either implies that you agree with their conclusion or you believe their valid evidence is insufficient to reach the conclusion. Either way, using the same type of evidence is not an effective way of making a counterargument.
TLDR:
The existence of counters does not determine the balance/imbalance of a card. This fact is also insufficient evidence to determine the balance/imbalance of a card.