Belief alone is not enough to convict someone, nor should it be. You need cold hard, demonstrable facts.
Trials are there to try and get justice for both the victim and the perpetrator, although people often forget the latter part. They're there so that you can't insist someone is beaten to a bloody pulp for nicking your sandwich, for example.
This is why things must be proved beyond reasonable doubt. The state has to be certain of guilt in order to take away someone's liberty.
I would not personally like to live in a society which thinks otherwise.
I don't doubt that the men are guilty as sin, the evidence is incontrovertible as far as I can see, but they have been tried and sentenced according to the law of the land.
Justice HAS been done. You may not like it, but - and here is the important part - that doesn't matter. You weren't at the trial. You did not hear all the evidence. You are neither judge nor juror.
The law is not there for vengeance, to satisfy the internet mobs thirst for revenge, or to keep people happy. It's amazing how often people forget that.