The same law exists in France, as far as I can tell; I happen to have encountered that due to signing up for a hosting provider (gandi.net) originally based in France, which noted that particular law in their terms.
I can see how such laws could seem like a good idea to someone completely unfamiliar with how the Internet operates ("Someone is wrong on the Internet!"). As it stands, it sounds like a good reason to never host anything in Italy or France that talks about other people in any way.
If the scope of it is as described I can't see how anyone s would think its a good idea, even if they support the general principle behind defamation laws and assume the internet works the same way as any other form of publishing. Unless they happened to be a public figure constantly in the press for consorting with prostitutes etcetera, of course.
If its scope is as described in the Wikipedia article it's akin to forcing newspapers to follow up every front page Berlusconi expose with a front page statement from Berlusconi that it didn't happen. Would the Italian public stand for that?
If you have a source about the French part I am really very interested. There is a similar law but it requires a judgment of a court of justice, it is a law about public slander and it usually only requires that the "attacked" party is given the ability to answer in the same medium.
France refers to it as the "Right of Reply", and as far as I can tell it requires no legal judgment to occur first. The "LCEN" ("Loi pour la confiance dans l'économie numérique", law on confidence in the digital economy) extends this to online communications. Anyone designated in online communication can send a reply within 3 months and force the publication of their reply in the same location as the original designation.
I can see how such laws could seem like a good idea to someone completely unfamiliar with how the Internet operates ("Someone is wrong on the Internet!"). As it stands, it sounds like a good reason to never host anything in Italy or France that talks about other people in any way.