The reason the presumption of innocence is important is because it becomes way too easy to create false evidence (or highlight circumstantial evidence) in order

The reason the presumption of innocence is important is because it becomes way too easy to create false evidence (or highlight circumstantial evidence) in order to sway public opinion. We should have a high threshold for evidence in any arena or we are otherwise way way too susceptible to manipulation. ...or perhaps, more generally - when an opposing entity exists that could conceivably manufacture poor quality evidence, then that should raise the bar of evidence required.