He was convicted of conspiracy, defined in the US as “an agreement of two or more people to commit a crime, or to accomplish a legal end through illegal actions. Conspiracy law usually does not require proof of specific intent by the defendants to injure any specific person to establish an illegal agreement. Instead, usually the law only requires the conspirators have agreed to engage in a certain illegal act. This is sometimes described as a “general intent” to violate the law.” [Forgive me, I snagged that from wikipedia]

So, he was in no way convicted of thinking, or fantasizing about bad things, he was convicted of conspiring to do those bad things.
The “because he thought it” sounds like desperate weasle-ese on the part of a doomed defense.

In the early days of the internet I discovered the world of news groups and the most extreme, bizarre and obscene forms of pornography. I am not a hyper-sensitive guy but my morbid curiosity left me with twinges of guilt and disgust for my brief exploration of the world of hard core news group porn.

One of the most extreme and disgusting categories is the graphic presentation (in drawings) of the torture and cannibalism of women.

The details of the sick fantasies are too disgusting to discuss, but they are similar enough to what this guy had in mind to ring a bell. I would wager that he indulged in this form of pornography and it may be the source of his intent to bring the fantasies to life.

To find that free speech apparently allows this kind of filth to exist and be circulated is enough to make me question how far we allow people to go with their “private” fantasies. I could not care less if certain people get a kick out of peeing on each other but when the fantasies involve torture and murder, it is going too far, regardless of whether it is a conspiracy or a fantasy.