I think they're probably correct, actually. As written, yes, this is not a GPL violation, they're not directly stopping you from redistributing what you were g

I think they're probably correct, actually. As written, yes, this is not a GPL violation, they're not directly stopping you from redistributing what you were given, they're just choosing to not do future business with you. In practice, judges often really hate people trying to do cute end runs around the intent of things, particularly anything that's more than a handshake, like a license. I would suspect they're betting heavily on nobody being big enough to be willing to try suing IBM-sized legal departments, and settling without losing the ability to argue this is valid if they're wrong.