Oh, and one more philosophical point:
The guiding principle of our criminal justice system is "innocent until proven guilty." What this means, in essence, is that a jury is supposed to assume innocence and only convict thereafter if evidence is presented that, in their minds, proves guilt beyond a reasonable doubt. So, jurors have a presumption of innocence and yet judges and lawyers all claim they are looking for "open-minded" jurors. This is not a contradiction of terms. A person can assume, in the absence of any evidence, that an allegation is untrue and yet still be willing to change their mind if evidence is presented. Your equation of open-mindedness with neutrality towards every proposed allegation, credible or not, is a definition you are entitled to. But it is not what most people associate with the term nor should they.