I don't think we've collectively figured out how to describe what "weights openly available" means, so open-source is probably a reasonable descriptor.
While it would be nice to have the data set Meta used I think open sourcing the weights is good enough.
Also, people who just want to be able to run something on their computer without paying money for it shouldn't call it "open source", unless it actually is.
These distinctions have been going on for decades, for very good reasons. No need to throw away that progress now.