Do you know of any alternative systems in place to resolve issues?
Even if Google wanted to form some sort of employee handled board or arbitration to decide how to handle accusations they would still be liable. And that is ignoring messy office politics involved in that sort of empowerment, bad actors, or just flaws of many parajudicial systems.
That companies would still be liable isn't neccessarily a bad thing as otherwise it could be delegated into a bigotted council and violate all sorts of discrimination laws at will. Any innovative system would need to address those issues as well.
They need to hire people that fit their culture better or change their culture to match their people.
This structure like most tools also has a dark use. Not as a "is bad" but "not automatically good". It could be used to perpetuate discrimination as the members don't want those <slurs> working in <their occupation>. As common for bigotry it is not a good move for long term health.
Anyway the sociality seems to be an underemphasised factor to unions. This isn't to say that the non people-to-people jobs should never unionize just that it is especially artifical like say the practice of putting rubber duck covering a fence post point - it is harder to set up and maintain as norm when the first question everyone asks is "Why bother with the duck?"
As far as I am aware there are no serious scientest unions - doctors boards are the closest thing but there are many significant differences.