Zuck knows this very well and it does him no honour to speak like, and from his position this equals attempt ate trying to change the present semantics of open source. Of course, others do that too - using the notion of open source to describe something very far from open.
What Meta is doing under his command can better be desdribed as releasing the resulting...build, so that it can be freely poked around and even put to work. But the result cannot be effectively reversed engineered.
Whats more ridiculous is that precisely because the result is not the source in its whole form, that these graphical structures can made available. Only thanks to the fact it is not traceable to the source, which makes the whole game not only closed, but like... sealed forever. An unfair retell of humanity's knowledge tossed around in very obscure container that nobody can reverse engineer.
how's that even remotely similar to open source?