As much as I agree with the fact that something had to be done regarding spammers, it is utterly wrong to remove an individual's liberty because "someone" did something bad.
I will not even bother myself going into the political implications of a childish behaviour like "hey, SOMEONE did something wrong, and you are paying for it".
Bleh.
This isn't political and liberty only comes into play if someone is restricting someone rights through violence or the threat of violence, not when someone places restrictions on a service they offer freely.
It may not be the optimal way to prevent spam and is at the very least ridiculously annoying, but definitely not a restriction of 'rights.'