You seem to be missing that arbitrators have a financial incentive to side with the company, which pays them? Explained in this video: https://news.ycombinator.com/item?id=49787720
I don't know how common this is, but yeah, this is a bare minimum that one should have with arbitration.
Very clear case, arbitration is fine. Fuzzy case, I would much prefer something that doesn't tip the scales in advance.
Note that the same bias problem exists with home inspectors. Realtors won't like inspectors that find things that kill deals. That one can be solved by hiring your own inspector with no input from the realtor.