There is much debate among scholars about negative campaigning, particularly concerning its efficacy. On this point, one thing is certain: negative campaigning exists because politicians and their advisers believe they work.
Looking at the question from a sociological perspective, however, would involve asking different questions. One might be the function that negative advertising, and negative campaigning more broadly, plays in a democratic society. A person could argue either for or against negative campaigning on this count.
It could be argued that negative campaigning exacerbates political polarization and division, which can contribute to a lack of social cohesion in society. A society where people cannot agree on very basic propositions lacks coherence, and this can contribute to disorder. On the other hand, the democratic process depends on the exchange of information, and it could be argued that negative campaigning does a better job of addressing important and pivotal issues than campaigning that is based on consensus-seeking and civility.
Another sociological question might be whether negative campaigning leads to popular disengagement from politics, thus contributing to lower voter turnouts and apathy. Both of these phenomena are dangerous to democracy. These, rather than the ethics or the efficacy of negative campaigning, are the kinds of criteria a sociologist would ask of a political strategy or approach.