As for open source - it is a developer prerogative.. as much as yours to use the app or not .. but it is NOT a crime - just another type of licence.. In fact pushing the "open source" down everyone's throat is hate ..

Does fountain let you use external NIP-46 signing devices for logging in? Because I'm not giving my nsec to a piece of closed source software.

I don't hate fees, I hate middlemen acting as banks. The issue with banks is fractional reserves that create new money out of thin air. This warps the economy and creates boom bust cycles as outlined as Fredrick Hayek. Instead, users should directly interact with Miners and the protocols.