People who are passionate about a project, as a user or contributor, do tend to ask what the status/roadmap of a project is. At least in open source projects I contribute to, that's not considered as demanding something from the project leaders, just because no one has paid for the project.
IMO, there are times where it's valid to state that no one has paid for the project so aren't entitled to anything, but I don't think this case is a valid one. I've seen this statement being used many times with open source projects and such project usually tend to lose sight that users are a central part of open source projects.
However, "There is absolutely no reason to not be answering emails" gave me the impression that at least one person is demanding replies to emails. I still feel it's okay to tell the quoted person that if he doesn't pay someone he can't demand from that person to answer emails.
Last but not least, if someone hasn't answered emails for some time, who seemingly had enough trust before to be important in a software project, then it may be wise, even for people with legit demands, to see whether or not that person had good reasons for his absense or not.
