To be honest, and trying to take a detatched view of the whole thing, the only people who will know the real truth are probably MJ and the boys concerned.
I think it's quite possible that MJ has never quite grown up mentally as far as loving other children goes. It's quite possible that whatever happened to HIM in his own childhood has left an indellible mark on him, and that he just wants to still be a young boy himself, and can't see that his actions and ideas are inappropriate at his current age.
From an outside view, it appears they've got his cross already built, and the trial is a mere front for what seems to be a determined effort on the part of the authorities to nail him to it.
I remember seeing the interview they filmed during 'The Making of Thriller' with the director, (was it Landis?) and how child-like MJ appeared then. It was as though he still wanted to be treated like a child then. Recent events are not a surprise to me when you look at it in that context. It's quite possible that he's being manipulated by his advisors who are getting as big a slice of the cake while they can, before the bubble bursts.
If there was irrefutable evidence, then I would say fair enough, he's guilty. I just wonder how much has been fabricated.
Incidentally, I am not particularly a MJ fan. I just don't feel without knowing the truth, I can condemn the man unfairly.
To return to the main point, I think that individual boys mature at all different ages into young men, and you can't truly define an age at which a young male is mature enough to take his own decisions on having sex.
The law has dictated an age, erring on the side of caution at which under normal circumstances, a young man ought to be able to make his own mind up. Unfortunately, some can and some can't. I think it's highly likely, though not a firm rule, that a male who is destined to be truly gay, knows what he wants to do at a far earlier age than someone say who might be slightly bisexual and still confused over his feelings.
I just don't think there is a hard and fast rule here, so the law errs on the side of caution.