All the respect for Rob Pike, but that makes no sense: learning ANY new language should be even easier for someone fresh out of school, and I imagine they set a high enough hiring bar to be sure that new engineers can adapt to whatever they are thrown at. All programming languages are easy to learn...
The harder part is figuring out process that are repeatable and result in high velocity and code quality, but I'd imagine that this is what an organization like Google is good at!