As happyout pointed out, if the juror believes that the evidence presented in a criminal case is inadequate to establish guilt beyond a reasonable doubt, then that juror is obligated to vote for acquital, regardless of how strong a "gut feeling" he or she may have as to the person's guilt. Juries are supposed to evaluate evidence, not shoot from the hip based on feelings.
I was on a jury once for a man who was accused of murder based on a technicality. It was accepted by all parties that he had not been the one who pulled the trigger. But under Massachusetts law (where I lived at the time), one who is a member of a group perpetrating a crime in which someone is murdered is as guilty of murder as the one who actually committed the deed. Had there been sufficient evidence to establish the defendant's presence at the scene of the killing, he should have been convicted.
Now, my gut feeling was that this guy was guilty. He clearly was a tight part of the group that had been present at the killing; these were people with whom he regularly hung around and perpetrated minor crimes. Additionally, he was clearly a thug, a gangbanger, a street criminal who was no stranger to violence. It seemed pretty clear to me that the best thing for society would be to get this guy off the streets for a long time to come.
There was a problem, though. The defense made a good case that there was a reasonable chance that, at the time of the killing, this particular defendant was not with his usual crowd, but was somewhere else doing something else (I don't remember where or what after all these years). Though I walked into the jury room prepared to send this guy away for life, discussions with fellow jurors and reexamination of the physical evidence led to the inescapable conclusion that, despite my strong "gut feeling," there certainly existed reasonable doubt as to whether this fellow was present at the time of the killing. Since there was no question as to his having done the killing personally, and the entire case against him was based upon his presence or absence at the scene, I eventually found myself voting for acquital on the murder charge - there was a lesser weapons charge that we convicted him of. He was sentenced to time served for the weapons charge and walked out of the courthouse a free man that very day.
My point in all of this is that, no matter how strongly a juror felt that MJ was a child molestor, the jury was bound to acquit him if the evidence was not sufficient to establish guilt beyond reasonable doubt. That is almost certainly what happened in this case, and if we believe that MJ is guilty (which I personally do), then we should probably blame the prosecution for not offering a good enough case to convict rather than blaming the jurors, who most likely did exactly what they were instructed by the judge to do.