Focusing specifically on the company's perspective, it's also a terrible option from a risk management perspective. It leaves them exposed to the possibility of a very expensive judgment. (Especially if it's a big well-known company that the courts might want to make an example of.) If they can resolve the dispute internally in a quick and satisfactory manner, then that is very much in the company's interest.
Which is exactly why it typically ends up being HR's job. And why it should officially be someone's job.
Framing it this way, I guess the company's internal culture being less dysfunctional because these sorts of problems are more likely to be addressed instead of being allowed to fester is just a happy side effect, but it bears mentioning, all the same.