Fair is relative. I ran the service as best I could for almost nine years. It became the largest in the world, but it was also a major time sink for me. I delivered a tremendous amount of value at no cost for a lot of people (200,000+ tech folks). I found a way to do it, and when I came to a point where it was becoming a distraction from other things I wanted to accomplish, I sold it. Do I think that was fair of me to do? Yes, I think it was very fair. I could have shut it down, started charging, etc.
The new owners have to manage it in the way they think best, and it seems like they are communicating their plans with lots of notice. They are also grandfathering in any users who were previous donators to EveryDNS with free service (minus a one-time $5 fee, which I think is reasonable). I think they have been fair in how they’ve managed the transition.
But, you didn’t ask if I think it’s frustrating there is no alternative to EveryDNS for people to migrate to. I do think that’s frustrating. Why don’t you start one? :-)