Why so passive?

After buddying it up with Strunk and White this past semester, I can't help but notice reporter's excessive use of passive voice in article headings. I found this article, which states:

"Nielsen's thesis is that the passive voice -- which is usually frowned upon by people who love good prose -- enables headline writers to "front-load" their heds with the key concepts from the story, making it easier for people scanning those headlines (as search results or feed headlines) to pick out their meaning more quickly."

An interesting thought, and maybe it will help me get over my annoyance of titles like this one (published in the New York Times on May 1): Costly Afghanistan Road Project Is Marred By Unsavory Alliances