I hate child porn and as a legitimate pornographer, I won't even talk to a potential model unless they can prove that they are at least 18 years of age.
With that said, I too have an issue with what is basically a thought crime. Think of all of those episodes of After School Specials, Dawson's Creek, hell, even Doogie Howser, MD where it was "depicted" that those under the age of 18 were having sex, even though the actual actors were aged 18 years of age or older. Under this law, everyone who viewed those episodes would be guilty and so would the producers.
But this concept of finding someone guilty of a thought crime is what has lead us to catching "internet predators". Don't get me wrong, I believe that they are out there, but the way we go after them is basically getting them for thought crimes.
Take the "To Catch A Predator" series that seemed to be on television every night on NBC. People posing as minors would ensnare (entrap) those who were willing to have sex with said "minor". The person shows up, only to find an NBC television crew and the police and are arrested. What crime was actually committed? And if the person who answered the "Lolita's" call are supposedly guilty of a crime, under this law, wouldn't the people posing as the "minor" be guilty as well?
We, as a society, need to decide if we truly want to prosecute people for thinking about something that if truly committed would be a crime or do we go after those who truly commit crimes?