It's not just protection against security, but also human error.
https://github.com/MrMEEE/bumblebee-Old-and-abbandoned/issues/123
https://hackaday.com/2024/01/20/how-a-steam-bug-once-deleted-all-of-someones-user-data/
Just because I trust someone to write a program in a modern language they are familier in, doesn't mean I trust them to write an install script in bash, especially given how many footguns bash has.
The SSPL requires that all software used to deploy SSPL software is open sourced. If I deploy my software on Windows, do I have to provide the source code for Windows? What about the proprietary hardware drivers, or Intel Management Engine?
The SSPL is not the next generation of licenses, it is effectively unusable. And both Redis and Mongo, dual licensed their software as the SSPL, and a proprietary license — effectively making their entire software proprietary.
Except Redis, and Mongo were making money. They had well valued, well earning SAAS offerings — it's just that the offerings integrated into existing cloud vendors would be more popular (because vendor lock in). They just wanted more money, and were hoping that by going proprietary, they could force customers away from the cloud offers to themselves, and massively increase their revenue.. They did not get that.
Another thing is that it's not "stealing" Mongo/Redis' when cloud vendors offer SAAS's of Mongo/Redis. Mongo/Redis, and their SAAS offerings, are only possible because the same cloud vendors put more money than Mongo/Redis make yearly into Linux and other software that powers the SAAS offerings of Mongo/Redis, like Kubernetes. Without that software, Mongo/Redis wouldn't have a SAAS offering at all.
I definitely think that it's bad when a piece of software doesn't get any funding it needs to develop, especially when it powers much more modern software, like XZ. But Mongo/Redis weren't suffering from a lack of funding at all. They're just mad they had to share their toys, and tried to take them away. But it didn't even matter in the end.