The company Redis only adopted the Redis project (and changed its name) a few years ago. Redis started as a community project and was run that way for almost a decade.

Why should that matter? I'm sure the percentage would be way smaller if this was the license used initially.

All clients will still be Open Source and a lot were initially written by the community as far as I'm aware, so they're actually still asking for free labor there.

About 75% afaik.

Never attribute to malice that which can be explained by stupidity

Reading the other comments the switch does make more sense, if you want to freeload off of the work redis has done for the project then you’ll have to join whatever community remains on the forked version, and anyone who cares about this kind of stuff should probably understand what’s permissible in the previous license, which clearly includes it being switched out like this