How can sociologists be effective and objective when studying and teaching controversial topics?

By sticking to Hard data/evidence as a basis to make their conclusions.

Explanation:

Sociologists studies how social interactions & social events affect individual behaviors.

Since, There were too many factors that can influence behaviors , it is really hard for sociologists to surely explain how humans behave in a certain way. This created a lot of division even among fellow sociologists.

So, it's important to create a quantitative value that can be used as a basis for measurements. Sociologists can find out whether a certain interactions/events is successful by using this numerical evidence.