Your agreement with the CC provider isn't binging for Valve, but Valve's aggreement with the CC provider is (which they need to even accept cards in the first place).
Admittedly, I don't know that much about the contracts between CC providers and merchants, but in the big picture of things, CC providers are the giants and Valve is the little guy, so I'm pretty sure Valve doesn't have a lot of leverage in those negotiations. Otherwise, presumably the CC provider would be unable to initiate the chargeback in the first place. The fact that the chargeback itself is successful (Valve's retaliation notwithstanding) is evidence that the contract between CC provider and Valve allows chargebacks.
In this particular case, what this probably means is that CC providers need to include a "no retaliation" clause in their contracts for customers who issue legitimate chargebacks. That's assuming CC providers care, and maybe they don't, but point is they have the power to fix this and if it becomes a problem for their customers presumably they will.
But I don't think any of this solves the broader issue though. In general I don't think you can depend on having a powerful authority like a CC provider side with you like this.
Admittedly, I don't know that much about the contracts between CC providers and merchants, but in the big picture of things, CC providers are the giants and Valve is the little guy, so I'm pretty sure Valve doesn't have a lot of leverage in those negotiations. Otherwise, presumably the CC provider would be unable to initiate the chargeback in the first place. The fact that the chargeback itself is successful (Valve's retaliation notwithstanding) is evidence that the contract between CC provider and Valve allows chargebacks.
In this particular case, what this probably means is that CC providers need to include a "no retaliation" clause in their contracts for customers who issue legitimate chargebacks. That's assuming CC providers care, and maybe they don't, but point is they have the power to fix this and if it becomes a problem for their customers presumably they will.
But I don't think any of this solves the broader issue though. In general I don't think you can depend on having a powerful authority like a CC provider side with you like this.