No, you can't really blame them. One could make the argument that once providing a service to users you have some responsibility towards them, but I don't think it overrides the case for them to be acquired.

I can't help feeling that there is something rather dreadful about this state of affairs, however. It just seems like too many good things get acquired and shut down. That could be the fault of the market/culture/prevailing business models/app stores in not making it profitable enough for developers to want to keep going with their single app, and it could also be the fault of the acquires for shutting down good things.

I'm unsure as to the solution.

I would say these acquisitions change lives of generations in a family.