Unions are not just for the purpose of getting fair pay, but rather about a broad case of being on equal footing with an employer, as stated in the parent comme

Unions are not just for the purpose of getting fair pay, but rather about a broad case of being on equal footing with an employer, as stated in the parent comment. Besides, this union is not just for salaried google employees, but also contractors etc - this will include for example cleaners and cafetaria employees, which are much more likely to be in need of the sort of union support that you mention.