If they do not want to do that, and instead would like each person who takes a copy of their work to pay for it, is that not also a choice they should have? Your choice as a consumer should then be to either pay that person for a copy, or not take a copy and move on.
Nobody is arguing that giving away music isn't a viable model for success - simply that it's not ethical to make that choice on behalf of content creators.
It should be fine for a developer (or musician, or other creator of content) to charge for their wares. If the app being available really is valueless or if the prospective customer doesn't believe it's worth what's being asked, they are free to move along and select a different product or to develop their own. I'm not sure why this concept is so looked down upon.
You're being an idealist - be more pragmatic and you'll live a life less angry.
I may only be speaking for myself here, but I honestly think the law will take a century to catch up here. We're on the frontier - with all the advantages and disadvantages that come with it (one advantage being, for example, the lack of any sort of regulation or licensing getting in the way of being a developer).
It's just sad that asking people to pay for things they take is being an idealist. I'm not angry. I just prefer to speak out against it than act like there's nothing wrong with it.
In another, less sophisticated time, you would have found a reality not far removed from the shop owner I described - and they would not have been considered lazy.
But a shop owner who railed against the shifting sands of humanity, pining for simpler times lost as he was pilfered blind, would clearly be sorrowful idealist.