The training data contains most likely insane amounts of copyrighted material. That’s why virtually none of the “open models” come with their training data
If that is the case then the weights must inherit all these copyrights. It has been shown (at least in image processing) that you can extract many training images from the weights, almost verbatim. Hiding the training data does not solve this issue.
But regardless of copyright issues, people here are complaining about the malicious use of the term "open source", to signify a completely different thing (more like "open api").
Not if it's a fair use (which is obviously the defence they're hoping for)