The idea that one is "innocent until proven guilty" beyond a "reasonable doubt" is a great standard for a legal system. I think it should be hard to justify using government power to take away a person's liberty. That said, there's no reason why we each need to use that same standard when making personal judgements.
For example, many people argued that it was wrong to declare Scott Peterson's guilt before his trial had even started. And sure, from a legal perspective we had to treat him as if he were innocent. However, anyone who paid attention to the news (unlike that idiot Amber Frey) had known for quite a while that Peterson murdered his wife. It was obvious. So obvious that he should have been executed without a trial? Of course not. But individuals can use whatever standards they want to judge each other, restricted only by their consciences.
Secondly, consider Michael Jackson. Sure, nothing has been proven in court, but it doesn't take a genius to interpret the evidence. He admits to sleeping in bed with strange children and says that he thinks it's normal. He surrounds himself with children all the time and separates them from their parents. When he gets accused of molestation (repeatedly) he pays out huge sums of money to make the charges go away. Should we throw him in jail without a trial? No. But it seems to me that there's more than enough evidence for someone to make a personal evaluation of the situation and rationally believe that he's a child molester.
Finally, consider OJ Simpson. He was actually acquitted of murder -- does that mean we all have a moral responsibility to act as if he's innocent? Duh, of course not. Everyone knows the guy did it, that's why he tries to maintain a low profile and doesn't get any more movie roles. A jury acquitted him, so he doesn't go to jail, but that doesn't prohibit us each from reaching our own conclusion on the matter and acting accordingly.