The entire internet is built on open-source technologies, as you probably know. That doesn't make the internet as a whole an open-source thing. Transport technologies are open, a lot of hardware and software around it is not, and that's still talking about the infrastructure, not what is actually running on top of all that.

It's like saying Windows is open-source because they use curl. And Microsoft is as open to open-source code as long as they can train their LLM on it and sell it to you. Sure they provide money and developers to some projects, but Windows, Office, Azure will most likely never be actually open to code investigations, forget free.