I have dealt with HR and I've seen these "well-intentioned" people turn on you so quickly. Sociopathy is the personality trait I would use to describe them.
Clinical sociopathy probably goes too far for most of them, but the outcomes aren't all that different anyway. I'd encourage people who still doubt or think highly of their ability to deal with HR, but who haven't had it tested yet, to actually engage with them on some low-stakes thing and see how it goes. My own main experience was effectively a complaint about several parents randomly bringing their kids in to run amok around the office. Of course HR wants an in person meeting to discuss further and to try and come off as more friendly. When the HR person pointed out how carefully my email was worded and how they shared it around with the other members of the office HR group to see, I was thinking holy crap, these people... And realized that despite me already being in the "not your friend" camp I had still underestimated them and even me being most careful would probably not be enough in any serious conflict.
Now I treat HR situations like a lot of other things: if you're in the situation and dealing with HR about something serious, it's already too late, your mistake was earlier. Optimize towards trying not to make the kinds of mistakes that lead to such situations in the first place, rather than how best to respond while in a bad situation. (Eventually there was a reminder sent out about bringing kids to work outside of any formal bring-them-to-work day being against office policy, as I expected, and for various good reasons some of which I had brought up too, and it stopped. So I got what I wanted out of the exercise, though I got a bit more too with how unsettling it was.)
