But I have no real basis for that, I would assume that based kickstarter and co also getting money from consumers without having to abide by any consumer rights.
I assume that the option of donating while keeping the software available free of charge would fall under the same category as getting gifts from strangers
Contrary getting displaying ads directly in the app would fall under commercial activity because you force the user of the app to give you money(via an ad provider)
If I give away the software but sell support, am I only liable to customers or to everyone? Similarly, if I let people opt in to commercialization of their data, am I liable to those that opt out? Does someone signing a terms of service qualify as commercial activity?
If I fork something and give it away can I sue the person I forked it from? If I tell people "YOU ARE NOT ALLOWED TO USE THIS BUT YOU CAN FORK IT" am I liable if they ignore me? Does a fork qualify as a new product or is the original author liable?
With the aim of not hampering innovation: (i) free and open-source software developed or supplied outside the course of commercial activity[1]
You are only in a commercial activity if you sell that product to that customer or you sold it to a distributor who then sold it to a customer.
E.g. if a customer doesn't buy from you he has no commercial activity with you so no liability.
I would argue that code is code and only becomes a non fungible product in the instance of selling it and only then the laws apply
[1]https://www.europarl.europa.eu/RegData/etudes/BRIE/2023/7393... => page 5 under the light gray box
Edit: fixed italics