At the end of the day, software developers need to eat. If they get to eat because their compensation model is driven by donations either before or after you use the app, who cares?

(Fair enough FOSS is free as in freedom, not just as in free beer, but I think that is moot to a lot of people, as long as the market space isn't crushed by anti-competitive buisness practices)

The bigger issue at hand here is negotiating fair API uses for instances and their admins, who also need to eat, and make the apps possible too.