Why is machine learning/NLP needed in this analysis? The categories/keywords are well known, and I believe that simple statistics would suffice to produce the

Why is machine learning/NLP needed in this analysis? The categories/keywords are well known, and I believe that simple statistics would suffice to produce the type of results shown. Of course, the text would have to be scanned and the dataset cleansed/filtered first. But those techniques predate ML/NLP.