What exactly do you mean by “hobby apps?” I’m slightly confused because it is pretty common to describe open source projects and the like as hobbyist programming, with all the expectations of customer service (specifically, none) that that entails.

If somebody is taking money for something, it isn’t really a hobby, it is a job. It might be a poorly paid one, but they still have an ethical obligation to their customers, to meet some standards of merchantability and provide some level of customer service.

But if you mean, “apps that hobbyists use” then that makes more sense. There’s nothing wrong with producing a toolkit that a hobbyist can use to write their own apps of course. It is like producing hand tools—you have an ethical obligation to make sure the tools themselves are reasonably free of defects but of course you don’t have to provide customer support for the treehouse!