They haven't taken anything away from the community though. You can still fork it and maintain it going forward. It's the same as if the entire redis team died in a bus crash.

What they did do is decide that in the future, their work won't be as easily taken advantage of.

If you think that your "social contract" has been violated that that is because you are mistaken about the contract you entered into.

This would only be immoral if you were misled or forced, and I'd argue that neither is the case here.

All the contributors gave their explicit permission to use their contribution in the way Redis does.

All contributors had plenty of freedom to spend their energy in projects under a license that specifically prevents what happened with Redis. It is not that they wouldn't have other options.

> which a single side has now altered.

No they haven't. "The community" submitted under a BSD licence, they literally gave anyone permission to take their code and relicence it under an alternative.

It's not like the BSD version of their code has disappeared. You can still use older versions of Redis that have their changes under BSD.

It sounds like submitters should have gone with GPL or AGPL if they wanted it to remain open source, available with the original licence for commercial use, etc.