GitHub is another fine example of a company who preaches open source, but doesn't have an open source product.
> The term "open source" has become a buzzword.
Nope, I'm pretty sure that its meaning remained the same since the term "open source" was founded. Feel free to prove my otherwise.
> Especially recently by the GitLab guys and their rhetoric.
Mind elaborating what rhetoric you're thinking of?
> GitHub is another fine example of a company who preaches open source, but doesn't have an open source product.
GitHub has a shit ton of open source products (https://github.com/github), out of which most popular example is probably Atom. The fact that their core product is not open source doesn't mean that they don't have an open source product at all. Bad phrasing perhaps?