I'd say that is a load of bullmalarkey. Attempted murder is one thing, but attempted downloading of content really doesn't fall under the same category. The guy they arrested never actually POSSESSED any porn (well, not according to this report anyway), so where was the harm done? A lot of people attempt things every day, but does that mean they should be punished simply for trying?
Personally I think that it crosses the line. If the FBI is going to arrest anybody, arrest the guys who MAKE the porn, not who downloads it. That does make me feel uncomfortable, though. I don't plan on downloading any child pornography any time soon and I do think it's very disgusting and should be looked down upon, but are they going to start going after all porn sites altogether? (90% of the internet, lol).