Human Resources and Business Objectives

I keep reading a lot about the alignment of human resources with business objectives, and it seems that there is a lot of resistance to the idea that HR metrics have to be able to align themselves with business needs, and I'm finding myself a bit confused. I mean, isn't it obvious that my job as an HR professional is all about aligning with the needs of the business? Isn't my job to find the best candidates for open positions, who will stay with the company longer, perform better, and generate more revenue? Shouldn't I be able to figure out an ROI with costs AND benefits all figured out and laid out on paper? I just really don't understand what the issue is all about. "Alignment of HR with business strategy" generates 1,800,000 hits, so clearly this is a topic people are talking about. Using your HR department for strictly administrative purposes is such a waste. People are one of the biggest costs for most businesses, so why wouldn't you bring HR into your business planning? And if your HR people aren't up to the task, then you need better HR people. HR decides who your workforce is. Better make sure they know what you really need!