The point is that he wasn't and isn't a kid! So, go ahead, tsk tsk away, but the truth is out there.
Where are you guys getting this "bombshell" that he was 18 when the IMs happened? In one of them he says "im not 18 till feb 23." So either 1) whoever said it was from 2003 was mistaken, or 2) the conversation happened in 2003 before feb 23.
Either way it doesn't matter, I don't think this debacle was about legality for most people.