I view Nate as basically acting like a sore loser here, which is why I find it unprofessional. I'm not arguing that we should clamp down on free speech or anything like that.
If a company wants to buy another company and sunset it, that's a normal business practice. I get that it's disappointing, but in no way is this "mistreatment." At least to me, this is a perfectly normal business situation that doesn't merit this level of complaining. It reads as an ex-employee being petty.
Funny, this story reads as ABC/Disney being petty to me. They were made a business offer to repurchase an IP that is worth nothing to them, and are instead choosing to blackhole any value it has and burn it to the ground because somebody with an ego has a personal grievance over Disney having been criticised for their management of the brand in the past. If that's what professional conduct entails in your eyes, I don't suppose there will be any agreement in our views.
I guess I feel like Nate should have anticipated this situation. By choosing to sell his company to a big conglomerate, this is the type of risk he opened himself up to. ABC/Disney certainly isn't blameless here, but this is the risk that any smaller company takes on when they get acquired. (The exact same thing happens to the startups that Google buys and then sunsets 12 months later.)
Big companies love to shut things down. Being so petty about something they don't actually want is less common and deserves loud mockery.