Sure it is. Jamis did this work for free, he doesn't owe you or anyone else any of his time to continue to maintain an application that he has burned out on.

Open source software gets abandoned all the time. This is only being discussed here because Jamis took the gentleman's approach and informed everyone that he was stepping down.

People say there isn't an entitlement mentality amongst people these days, but this kind of reaction is pretty compelling evidence that there is.