This feels somewhat analogous to games like Quake being open-sourced though still needing the user to provide the original game data files.
In terms of functional role, if we're to compare the models to open-sourced games, then all that's been open-sourced is the trivial[0] bit of code that does the inference.
Maybe a more adequate comparison would be a SoC running a Linux kernel with a big NVidia or Qualcomm binary blob in the middle of it? Sure, the Linux kernel is open source, but we wouldn't call the SoC "open source", because all that makes it what it is (software-side) is hidden in a proprietary binary.
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[0] - In the sense that there's not much of it, and it's possible to reproduce from papers.