Contract workers are not employees they are temporary hired hands they get fired and reallocated on company whim for company purposes, that is the nature of their jobs, they are easier to fire and hire than full time 401k employees. Not everyone gets the company car home with them.
What disturbs me is that you keep pointing to the fact that they are mostly minorities as if Google deliberately chose minority workers for these jobs, the sad fact is that these low end jobs are typically occupied by minorities.