Open source as originally defined by Christine Paterson, the inventor of the term refers to software the includes the freedom to view, modify, and distribute the software's source code.
By the original definition of the term by its inventor, the FUTO license absolutely is a valid open source license.
You may be referring to the OSI’s definition of open-source according to the Open Source Definition (OSD). If so you should clarify that this is the case.
The Open Source Initiative took the original definition of open-source and modified it to include terms protecting the ability for a user to commercially exploit the software or make it closed-source without compensating the original authors.
I suspect (but cannot prove) that the OSI defintion was influenced by their very large big tech donors including Microsoft, Google and Apple who all benefit significantly from this small change to the definition.
By the original definition of the term by its inventor, the FUTO license absolutely is a valid open source license.
You may be referring to the OSI’s definition of open-source according to the Open Source Definition (OSD). If so you should clarify that this is the case.
The Open Source Initiative took the original definition of open-source and modified it to include terms protecting the ability for a user to commercially exploit the software or make it closed-source without compensating the original authors.
I suspect (but cannot prove) that the OSI defintion was influenced by their very large big tech donors including Microsoft, Google and Apple who all benefit significantly from this small change to the definition.