I'm often disappointed to learn that is exactly how most people close sites. No notice, no warning, and no answers.It's a shame you couldn't put a simple explanation along these lines on your site to say why it had closed, instead of leaving people worrying if you had problems, then spending time messaging you to ask (and not getting a response). It's all very well asking people to "move on" but just deleting the site with no explanation and not replying to messages about it doesn't actually enable people to do that!!!
This is why when someone looks to close a site, I hope they at least consider either giving some notice or passing it onto someone else.
Such advents have given me the opportunity to have taken over several other communities over the years (sometimes merging them into site and sometimes leaving them to stand on their own).
At least this way community members don't feel abandon. And they're given a chance to continue their friendships either on that site or else where. Rather than being left in the cold.
I guess its a personal preference