Take a look at the headline for this AP article:

The phrase “Pope defends family” in this headline implies two things: That “family” does not include gays, and that “family” needs defending from them. (And, looking at the article more broadly, it also implies that a divorced parent and his or her children are not a “family,” either -- and neither is a couple including a woman who has had an abortion.)

The Pope didn't “defend family.” He articulated his view of what constitutes a family and what threatens it. A headline stipulating to that view is pretty much the opposite of impartial journalism.

Don't see the difference? Try to imagine the AP using the headline “Speech defends family” for an article about a speech in which someone embraces gay marriage, single-parent households, and reproductive rights.