There’s no third option between FOSS and proprietary (unless there are licenses that match the Free Software definition but not the Open Source definition or vice versa, I suppose, but I’m not aware of any). All software that is not FOSS is proprietary by definition, whether the source is available or not. It’s not “disingenuous” to call FUTO software proprietary. It’s simply factual.
There’s no third option between FOSS and proprietary (unless there are licenses that match the Free Software definition but not the Open Source definition or vice versa, I suppose, but I’m not aware of any). All software that is not FOSS is proprietary by definition, whether the source is available or not. It’s not “disingenuous” to call FUTO software proprietary. It’s simply factual.