Look, I get tons of spam: I have had the same email address since 1997 and have never been shy about posting it anywhere and for any purpose with visibility to anyone. However, spam filters actually work well, and to the extent that don't work it doesn't take much time to deal with: spam is very obvious. When spam isn't obvious, I will argue it is actually a malicious phishing attack, and not spam.
Given this, you must realize that >99% of this spam is from random people whom are not actually subject to this law because they aren't at all traceable. If I have heard of the service, then it will be trivial enough to killfile (such as, "reject all messages from this domain; example: *@pcworld.com"), and much easier to do so than even clicking a single link to unsubscribe as you can make that a hotkey in your client.
(Sadly, people believe that they should rely on spam filters for this use case, which is ludicrous as there is no real way to differentiate "I signed up for PCWorld in 1999 and have since decided I no longer care" from "I never signed up for PCWorld, but they decided to start sending me things O hate" from "I like PCWorld and would love to hear about their new articles, so I subscribed" using remotely objective algorithms.)
(Even a human is going to get it wrong half the time, especially of they're as spam-touchy as the people on this thread reporting services I might personally use and like to Google as "spam" when they can and should either killfile the sender or take the extra 30 seconds to unsubscribe; people who do this just damage the effectiveness of spam filters by messing up the training sets with data that isn't truly indicative of the spam we need machine learning to filter.)
In essence, this law spends a bunch of time figuring out how to regulate people who were either never the problem in the first place, or we're the problem only because they decided to hand your email address to a third party they maybe shouldn't have (although the idea that you will combat spam by keeping your email secret is already a losing battle). Meanwhile, the people who cause the >150k spam messages I receieve per year to saurik@saurik.com just get to keep on spamming.