Via Tyler Cowen, here's a defense of "pink slime", also quoting a NYTimes blogger. The short version is that it's been used in ground beef since beef prices soared in the '70's (our going off gold, jump in grain prices as USSR started buying, etc.), has been safe since Jack in the Box went out of business in the 90's, and makes hamburger lower in fat..
The defense makes sense, but it assumes consumers really want to understand how food gets on their table. In my cynical view today, they don't, because if they did they'd face much higher food bills.. The food movement will be able to whack a few moles, artisanal food producers will be able to find some niches, but the vast majority of the food that goes on our tables will be produced by "industrial agriculture".