I may be misremembering but I think that at the time, Logica was the work of one developer who happened to be at Google. I'm not sure that there was an institutional push to use this language, nor that it has significant adoption at Google itself.
I don't think that matters? github.com/google has a bunch of projects with large warnings that "This is not a Google project", not sure why or how that is. From the outside it looks like if you work at Google, they take ownership of anything you write.
That is precisely how it works.
Disclaimer: I am not a lawyer, and I'm sure the validity and enforceability of the relevant contract clauses varies by jurisdiction.