"to form an opinion about through careful weighing of evidence and testing of premises"
Being judgmental is a good thing. We should carefully weigh evidence to determine if something is morally and legally acceptable. I'm allowed to judge you and decide that what you are doing is wrong. If I know what is right or wrong based on my moral foundation, I can learn from others' mistakes before I make them myself.
However, I need to stop the process before I get to the sentencing stage. That's really where the danger lies.