The NLRB ruled that the nature of their work makes them employees of both Cognizant and Google, despite whatever those companies try to classify them as, and that both are required to negotiate with the union. Google is now just flat-out refusing to respect that decision.
I was a "contractor" for JnJ. Which ok, is a different company but it's the same premise. The reason they contract the work out is so they can avoid giving benefits and cut costs for an essential job. All so when something like this happens they can just pass the buck off to the contracting company saying it's not their responsibility for the working conditions they set.