What FUTO didn’t (doesn’t?) understand is that open source licenses exist to protect the user’s rights, not the developer’s.
Creating their own license to protect their own rights is perfectly fine, they just can’t be calling it “open source” anymore once the terms infringe on the user’s rights (especially in a discriminatory way) for the benefit of the developers.
Open source licenses are what allowed the community to create Redict or the Linux Foundation to create Valkey when Redis went to shit for example. I suspect that the same wouldn’t happen for any of FUTO’s work due to their Source First license, which is a pretty big loss the user experiences in terms of reassurance that their software can be maintained long-term.