I got a couple silver proof sets earlier this year and had to send them back three times before I got acceptable ones. Acceptable meaning that the only ugly coins were the dollars with the unpopular presidents. The unacceptable sets didn't just have slight toning or something, they had really bad spots, and in one case, there was actual pitting on Sacagawea.
I think the majority of what the mint sends out must be like this, but nobody really looks at it. They just go right into their dealer stock or get wrapped as presents. Either that, or I'm the unluckiest guy in the world, having 2/5 problem coins in my ASE set and 6/8 bad silver proof sets.
Looking at the proof again, the squiggly bit between "FINE" and "SILVER" might be struck-through a fiber of some kind (no, that's not lint on the holder - that's a groove on the coin). Regardless, the damage around "S" in states and the rim-ding next to it are really unacceptable. It's not possible that anyone inspected the coin at all before packaging it.