Right you say that, but I swear this view is some kind of really fucking weird Americanism that y'all take as gospel truth.

I've interacted with HR teams at a couple of jobs in the UK. These interactions have been fine. They have been there as the contact people to make sure I get paid for my work, that I can access my benefits, and that I am subject to the procedures and processes that I'm entitled to.

They are paid by the company and therefore they of course work for the company – and part of that job is ensuring compliance. But this is the same as e.g. a security officer, or a health and safety officer, or any number of other roles the involve running companies correctly and in accordance with best practices in a way that can benefit both company and staff. It's not an "either-or" situation!

I think the big 'Americanism' comes from the somewhat two faced nature of HR culture in the States - HR are (generally!) the people being super friendly and coming up with "the company is one big family aren't we so happy together" events and whatnot. They're also the people who, in my experience, have mostly bought into the MBA-isms about maximizing value in all things, which includes screwing over said employees as much as possible through legal, yet sketchy methods that make a lot of sense if you're treating employees as resources, not humans.