Wow, today I learned that in some countries, the supermarkets keep their eggs in the refrigerator! Apparently there is a protective coat on eggs that sometimes gets washed away, and when it is, you need to store the egg in a cold environment otherwise bacteria gets in. In other places, eggs aren't washed (that much at least) so the protective coat is still there, so we store our eggs on normal room temperature shelves.
They are probably washed, but only minimally - sometimes there is still a small feather or some dirt on an egg.
They're still washed, otherwise they would have all kinds of crap on them (literally, chickens only have one hole), they just aren't subjected to chemicals and scrubbing etc.
Having very low salmonella rates in the flock makes it really unnecessary
The eggs I buy in my supermarket don't have literally crap on them, but it isn't uncommon that they have bit of dirt or hay/grass on them, and those are bought from a mainstream supermarket chain. I do realize they obviously do a quick cleaning pass regardless, just wanted to clarify that many eggs aren't pristine when bought :)