He didn’t think he was communicating with a child; he thought he was communicating with her mother.
Indeed, he was conversing with whom he thought was the mother. The guy actually believed it, but the same applies to the pervs caught on Dateline NBC. He actually believed a mother would allow her 7 yr old daughter to be transported to the Virgin Islands (pun intended) for sex and actually said he could ply her with liquor.
The stupidity. It’s much like the story of former N.E. Patriot Aaron Hernandez who is accused to killing two men, one of whom bumped into him at a nightclub and spilled his drink. He apparently shot the men to death in a car, then killed another ‘friend’ (the others were strangers) who ‘knew too much’. Hernandez had just signed a $40 M contract. Instead he’ll prob spend rest of his life in jail. Simply stupid.
You know why it's so hard to prosecute cases like this? Because the prosecution has no way of getting around a defendant who simply says: "Yeah, I said/did all those things. But I knew I was talking to an adult, not a child." Or in the Dave Herman case, the defense could very well have been based on a strategy that Herman knew all along that the child was fictitious.
If it sounds strange, just step back and ask yourself how a TV network can go out and set up an entire series of shows about catching child sex predators ... and yet none of the people involved in any of those cases is ever prosecuted.