That's rude. Yes, I've contributed to a few. However, here is a list of open-source software that've notoriously turned to unethical decisions when pressured into getting funding.

Audacity: Free until 2021 when they were bought and introduced telemetry.

Streamlabs: Open-source but tried to monetise and attack the OBS brand

Bitwarden forks: Various forks of open-source code that included monetisation

OpenOffice: Great desktop apps until bought by Oracle

CCleaner: "free" software that contained trojens.

HoverZoom: Chrome plugin sold by original dev, new update included spyware and ads.

As I said, I don't mind if the answer is "we are volunteers who love this", but I do ask that formal webpage presenting a product, that even has an FAQ page, explains it's funding model. Their github (https://github.com/CelestiaProject/Celestia) is much better at this.