Should Merit be considered in Court?

When watching the documentary on Harvey Milk (which was awesome by the way), what stuck out to me the most was the guilty conviction of 2 accounts of aggrivated murder, and only a (I believe it was) 4 year inprisonment with opportunity for parole. My first thought was that this was probably because he is a generic of sorts, and social systems love to see this type succeed. But i think this is a half truth, a little too hasty. He was a congressman, an ex firefighter, he was an active participant and contributor to San Francisco at the time before the murder. While I agree with the class in that his sentence was a joke, and should have probably been either life or death, my question really is this: should a persons prior contributions to society and good marks be factored into the outcome of a court case? I believe that these merits are really only considered if you do fall into the norm, however, if we were to apply these merits to every court case, even a gay black man fighting a DUI, would this be a better or worse case scenario than strictly reading the incident itself, and judging based off of this one abstraction of a life?