It means that making your peers looks bad is as important as making yourself look good. There's only so many spots for promotion, so employees have to stab each other in the back in order to look impressive enough to be promoted.
Not sure that's a culture that only exists at Google... pretty much true at the higher levels of almost any big company that I've worked at.
i’ve only noticed at least teams/products in google that are more stagnant or don’t have as much work to do. therefore they compete and are territorial with the work. other products that are growing there is plenty for everyone