Sure, in this case Conservancy aren't a party to the GPL contract, but as a recipient of GPLed binary code from Vizio they are a third-party beneficiary of the

Sure, in this case Conservancy aren't a party to the GPL contract, but as a recipient of GPLed binary code from Vizio they are a third-party beneficiary of the contract between Vizio and copyright holders. Actually Conservancy also are representatives of copyright holders in Linux and other software used on Vizio devices. So if they lose the third-party beneficiary suit, there will be a copyright angle they can pursue as well. GPL lawsuits aren't about hardware repair, they are about software repair and the rights given to end-users by the GPL license/contract. You don't need source code to replace broken components on a tractor, you need repairer/vendor software that performs pairing of DRM-locked parts.