I've been on both sides of this sort of divide, as both insider and outsider.

It's easy to see it as politics. I do, pretty much all the time, but that's because I have a background in politics. I'm primed to assume the worst.

I think the explanation is simpler. If you are a Googler, you mostly talk to Googlers, you mostly come to quick consensus that way, and it all makes sense to you and the Googlers you had casual whiteboarding sessions with. So you just go ahead with the to-you-obviously-best decision and get surprised when non-Googlers are mad at being presented with a fait accompli.

There is no ill-will and no conspiracy required. Some of the personnel allocations are driven by corporate strategy, but folks engineering on the line are all reasonable human beings. It's just simple personal dynamics. You talk mostly to the people closest to you unless sustained effort is made to keep stuff in the open.