They posit you can still modify (tune) the distributed models without the training source. You can also modify a binary executable without its source code. Frankly that's unacceptable if we actually care about the human beings using the software.
A key pillar of freedom as it relates to software is reproducibility. The ability to build a tool from scratch, in your own environment, with your own parameters, is absolutely indispensable to both learning how the tool works and changing the tool to better serve your needs, especially if your needs fall on the outskirts of the bell curve.
There's also the issue of auditability. If you can't run the full build process yourself, producing your own results from scratch in a trusted environment to compare with what's distributed, it becomes exponentially harder to verify any claims about how a tool supposedly works.
Without the training data, this all becomes impossible for AI models. The OSI knows this. They're choosing to ignore it for the sake of expediency for the companies paying their bills, who want to claim "open" because it sounds good while actually hiding the (largely stolen and fraudulently or non-consentually acquired) source material of their current models.
Do we want a new definition of "open source" that actively thwarts analysis and tinkering, two fundamental requirements of software that respects human beings today? Reject this nonsense.
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