That's a pretty terrible analogy. Etymologically they bear no resemblance to "open source". A better analogy would be "low fat" or "sugar free".
The more appropriate analogy would be if the Sugar Free Initiative defined "sugar free" and then you correct me by saying "actually that beverage isn't sugar free, it's artificially sweetened".
The world would be a better, more accessible place if we instead focused on what things are or are not, like preferring "OSI Approved License" over "open source" rather than needlessly conflate complex meaning with otherwise simple terminology.
