The companies involved were both resellers of Dish Network's service, and were fined for different reasons. One company was fined for calling people who were listed in the registry, and the other was making automated calls that led to no one. The fines the FTC was originally after were much higher, well over a combined $11 million.
It is unfortunate that a similar system for email would be nearly impossible to implement and even more impossible to enforce. The FTC is one of many groups that pursues spammers, and fines them when possible, but the problem is just too massive to take on.