cbg, I think in a perfect world your position is correct. As a practical matter, it's kinda not. Whereas it may be true for you, that doesn't mean it's true as a general rule. ... the same way that most lawyers take great offense at the notion that they are no more ethical/good at their work than any other segment of the human population (and indeed one can point to a distinct lack of integrity in all but a minority, depending on what motivates them). This whereas I having spent 25 years in the world of law know damn well that many personality disordered-types (narcissism for one) tend to be drawn to the law and usually to specific areas of practice (e.g., trial law), just as those types are drawn to the world of entertainment. (There is a reason, after all, that most politicians start out as lawyers ... and it's not because their primary goal is to make law, but to have folks court their favor and wield influence over others.)
"HR does not "work for" either managment or workers."
Huh? Then please define "work for".
"HR is there to see that the laws are followed and that company policies, or exceptions thereto, do not violate any laws."
While a component of human resources positions may be just so, regulatory compliance cannot be said to be the sole or primary function. (If true, then HR jobs would literally be a revolving door in most places, because integrity would demand that people not work in a firm where laws are routinely overlooked or flouted for the sake of expedience or benefit to the company.)
"... we don't have the final say in what policies exist or when to make exceptions or even who to hire and fire."
As to the first part, possibly true (depending on the place); as to the second, it depends on what powers are conferred upon them.
"Often managment makes decisions over our protests..."
While this may be true in your case, I think it's better not to state as though a general rule.
"... and we get used as the boogey man by managers who don't want to do their jobs."
In general, agreed.