That's exactly my point: It still benefits the maintainer. So they benefited from contributors, then fucked them over later, violating the social contract (but not necessarily the software license because CLAs yadda yadda).
Again, my point in response is that the contributor received more benefits (in the form of code review and ongoing maintenance) than the maintainer. We're talking in circles here.
As long as the contributor isn't a cloud provider, they can continue to use the software unimpeded under the new license. Their contribution continues to be maintained by the maintainers. The contributor hasn't been "fucked over" in any way.
If the contributor is a cloud provider, they can choose to enter into a commercial licensing / revenue share agreement and continue to use the software unimpeded. Or they can decline and use/create a fork, in which case any so-called fucking-over is clearly mutual, because the contributor wants to profit from the software explicitly without making its ongoing development financially sustainable for its original maintainers. That's parasitic behavior.
I must ask, have you contributed to Redis? Or are you just expressing outrage on behalf of other people who actually contributed to Redis and may not actually even share in said outrage?
If the latter, why are you so emotionally invested in this topic? And have you ever been on the other side of the coin, maintaining a widely-used open source project?