Oh they definitely can say other things. It's just that it would be inconvenient. They might lose money.
I wonder if the laws and legal procedures are written considering this general assumption that a party to a lawsuit will naturally lie if it is in their interest. And then I read articles and comments about a "trust based society"...
I'm not taking one side or the other in the case itself, but it's lazy and superficial to suggest that the defendant in a civil suit would say anything other than that the suit has no merit. The version of this statement where they generously interpret anything the NYT (I subscribe) says, they might as well just surrender.
I'm not sticking up for OpenAI so much as just for decent, interesting threads here.
This is the nature of the civil court system – it exists for when parties disagree.
Why would a defendant who agrees a case has merit go to court at all? Much easier (and generally less expensive) to make the other party whole, assuming the parties agree on what "whole" is. And if they don't agree on what "whole" is, we are back to square one and of course you'd maintain that the other side's suit is baseless.