The faux-open models mean the models can't be used in competing products. The open code base means enthusiasts and amateurs and other people hack on Meta projects and contribute improvements.

They get free R&D and suppress competition, while looking like they have principles. Yann is clueless about open source principles, or the models would have been Apache or some other comparably open license. It's all ruthless corporate strategy, regardless of the mouth noises coming out of various meta employees.