Eggs-actly why do Americans refrigerate eggs?

Penny, Betty and Veronica, ©2013, Lori Korleski Richardson

As a home poultry keeper, I was told NOT to wash eggs and that they would keep much longer unwashed. (Not that I ever got too many eggs.) So it always made me wonder why commercial egg producers did so. I figured that the hens were kept in such squalor that it was necessary.

But the real eye opener in the article below was that there is actually a vaccine against salmonella and that it's not required in the United States. Really? When you have to search for chicken feed that doesn't have antibiotics? When we've had so many cases of salmonella that almost no one makes a good Caesar salad dressing anymore and all eggs (low in fat and a good, inexpensive source of protein) are suspect?

In a somewhat related vein, how can my dog be vaccinated for Lyme disease, and although I live on property frequented by deer, and have found several ticks on me, there's no vaccine for me?

The egg article is here: http://io9.com/americans-why-do-you-keep-refrigerating-your-eggs-1465309529