Is every company having a HR department not enough?
Basically, it's irrational to try to cover up or ignore harassment in the vast majority of cases. Which is why HR is a perfectly decent solution for most of these issues, and we only hear about a few outliers in the media / law suits.
Engineers are also supposed to build bug-free software, but when your boss tells you to ship the product, you're going to ship it. If the company gets sued because your product has bugs, you're not going to be personally liable.
how did you reach that assessment? this would seem to only apply to behavior that was openly visible and recurring.
I believe HR departments handle this sort of thing very well in the vast majority of cases.
If that's true, which it may well be in that case, I'd say that Uber is an exception to the rule and the HR department was simply run in a (frankly) idiotic and irrational manner.
HR departments are intended to protect the company from liability. Generally speaking, they do that by taking standardized actions regarding harassment claims because otherwise they open the company up to lawsuits and negative PR. (see Uber)
Most company HR departments take harassment VERY seriously for this reason, especially if the harassment was written in black and white, such as Susan Fowler claims her harassment was.