I've always been broadly under the impression that the HR department was a waste of air, but I suppose conflict resolution is perhaps something they'd be useful for.
...maybe.
...maybe.
Of course, this means they may be at times too conservative in the interests of having an easy life. Doesn't mean they're not useful at all.
I think a balance of conservative and progressive opinion is required for almost any organisation to operate effectively: (genunie) progressives drive us forward, and (genuine) conservatives stop us going over the cliff - it is pretty much as simple as that. Unfortunately, finding the appropriate balance for any particular situation can be extremely tricky, so largely we get it wrong, and just stumble along, grumbling to ourselves about how stupid and ineffective everything is.
On the assumption that there are genuine problems within Github, hopefully this situation will at least give them a chance to engage in a bit of rebalancing, and find a more sustainable path for their future. This is, of course, the problem of solving problems by trial and error - you have to deal with the errors, and in cases like this the errors can be quite painful for the people involved.
The problem with legal is that the safe position is always "no". So, finding legal who understands that businesses sometimes have to take a risk, and we need to know if this is "illegal" as opposed to "inadvisable, because it's going to cost money" as opposed to "inadvisable, because it might cost money but might be worth the payoff" is not easy.
HR is simply useless. It's only useful tasks are all effectively part of "legal". It can't make useful decisions on hiring and actually gets in the way. Any employee with a genuine grievance knows that HR is the companies rep, not yours. Oh, and they generally have access to a whole bunch of things that stir up hideous amounts of politics (salaries, reviews, promotions, etc.) So, what's left that's useful? Nothing.
So while for a single employee HR might seem like a waste of air, it's elementary for any business with a reasonable number of employees.
An HR department absolutely works to protect the company, but a good HR department will also work to protect the employees, because in the long view that is also beneficial to the company. And many HR people who I've talked to specifically enjoy their jobs because they like working to make employees lives better. Where their directives conflict with that they will try to fight the directives.
Certainly in some cases where there is a unresolvable conflict between employee and employer, HR will work against the employee. But for a good HR department those situations should be very few. A good HR department will be able to project forward into a long enough view that they can find ways to move forward amicably that protect both the employee and the employer, to everyone's benefit.