I've re-read this a few times and I'm still not sure what "harmful to open source" means in this sentence, could you expand on this a bit when you have time? (readings I considered: this will dissuade people from using OSI licenses, this will dissuade people from trying to monetize open source components, this will dissuade people from using open source components in their products all together, this will dissuade people from contributing to open source)
> Many people had contributed their efforts to the Redis project for free
This one is not directly addressed at OP but I would be interested to see what the contribution numbers are like for Redis and other projects post-license change.
In my own limited experience (project with >10k, <100k end users), I received no meaningful code contributions when the project was MIT licensed, but contributions of significant features and large bug fixes skyrocketed after switching away from it (not saying that the license change is the reason for that, just that it didn't dissuade some people who are willing to contribute significant effort from contributing to the project).
Editing this post to say thanks for the response and clarity, I don't have anything else to add!