Read between the lines:

"The private sector funds most global research and development, and many of the results of such work are not published in peer-reviewed journals."

I read this as:

Given the option of publishing pseudocode and not publishing at all, Nature is willing to accept the first.

and

Google would likely not have published if we required full transparency, and having them publish is more beneficial. (and this paper is impactful enough that it is worth making an exemption for.)

And in my opinion:

People are asking too much of Alphabet. Alphabet could easily choose not to publish anything. To be honest, I'm shocked that they do publish.