In my experience, in such a competitive (read:overly-capatalist!) environment, where everyone is looking to squeeze the pennies, H&S will always be hard to get the 'buy-in' from managers, senior or not, because they like finance people who can say "oh, I saved you £5,000 yesterday" or the supplier, who says "we can reduce your contract cost by 25%", then us H&S people come along and say "well, if we do this - which will cost £2,500 today, we may well save a life tomorrow" - this of course doesn't sit with their understanding of economics, and thus H&S gets seen as a thorn in the organisation's side, rather than a help.
I also think the media has a large portion of blame (and it doesn't help with the Tories last year practically arguing to repeal H&S laws), however within an organisation, if the top-level don't filter down the importance and usefulness of H&S, then the culture is there - but it's a negative one.
I've found that my interaction with staff has been positive, but working in manufacturing (both food and non-food) despite all the messages about how H&S is top priority, it's ALWAYS production - get the stuff out the door, no matter what!
So whilst I have good relationships, when you ask someone nicely to take that pallet truck out of the walkway that's just been dumped there (because an alarm went off on a line and that's a higher priority than someone's potentially broken legs) it's seen as a burden, and sometimes a rolled-eyes reply! This to me, then, shows that their supervisors aren't making a positive culture, nor their manager, nor the senior manager and so on.
So ultimately, I find that £$ is the big driver of a "bad" (or in fairness, lazy) cultures to H&S.
This, of course, doesn't get me onto poor policies, good-but-not-enacted policies, strange procedures, beaurocracy....but none of us have all day! :)