One of the risks inherent in running a business is encountering those operating in bad faith. Or even those operating under a belief that they are operating in good faith, but aren't. Or those that are operating in good faith, but in a situation, for whatever reason, that someone has to lose.
In other words, be prepared. Part of your responsibility if you are running a business, big or small.
Maybe that was malicious on Hasbro's part. Maybe they didn't think of that. Either way, it doesn't matter if you are running a company. Be prepared for every eventuality. Do right by your employees by being prepared. It's part of your job. The world will not be fair to you. Sometimes the reasons are justified. Sometimes the reasons are that you are dealing with a complete scumbag. Either way, don't complain. Figure it out. If you are responsible for the livelihoods of others, I would hope that you step up and figure out this problem instead of sitting down and complaining about it.
I see your point. But look at it from their point of view. They entered an agreement (that they should have been more on top of at the time) that they felt was hurting them. And legitimately so. At face value, this agreement looks like a terrible deal for Hasbro. That opinion was misguided in my opinion and Hasbro should have kept with the status quo, for many reasons (although the outcome of this debacle did benefit smaller publishers in the long run, so maybe this nonsense was good for them, perversely).
If you had signed a cell phone contract, with all kinds of sweet benefits, but later realised that as part of your contract, you were being asked to share your number with telemarketers or some equally horrible thing... would you not want the opportunity to renegotiate that contract?