Law does not run on a CPU with certainty. There is risk analysis going on: there are many jurisdictions at play. When you are big enough, something that has fundamentally viral characteristics by design can have catastrophic impact even if reading of the license as linked would be almost certainly accepted as correct and likely. Therefore, especially for a company like Google that has a unified codebase, that treatment is justified. So goes for other big companies who would be at least wary of just taking AGPL.