I had this exact same problem from both sides (not working on a project any more and wanting to find someone to maintain it/wanting to maintain a project someone wasn't working on because I found it interesting). It's not always easy to find people who are interested, and, while giving maintainer access to someone you know very little is usually fine and works out great, sometimes you get results like these.
In the end, I built something to "solve" this, a project called Code Shelter[1]. It's a community of vetted maintainers that want to help maintain abandoned FOSS projects, so if you want your project to live on but don't want to do it yourself, you just add it there and you can be reasonably sure that nothing like this will happen to it.
Of course, you have to get a large enough pool of trusted maintainers that someone will be interested in each project, but it's still better than blindly adding people. I can't fault the maintainer of that project, since trusting people is usually fine, but it's too bad this happened to him. The commenters are acting a bit entitled too, but I guess it's the tradeoff of activity vs security.