Newark (and well every city) is affected directly by the people that live there. To say otherwise would ignore the citizens of whatever city, and their effect on their city. Lets face it Newark is not a very "good" city in general but the vast majority of people that live in Newark are good people. As with all areas a small percentage of the population is what is considered "bad", and well those give any city the rep it has (as far a negative).
I have seen enough of newark and goings on to know that it is generally not safe (day or night), for the most part regardless of the area you are in.