The article does dissect the difference between weight loss drugs and dieting in general. Where they found that muscle mass loss was higher in those that took the drug as opposed to those who followed a calorie restricted diet.
To your point, the drug is absolutely to do with it if by taking the drug people need to be more mindful of the types of food they eat, if they have a smaller window to consume nutrients.
It is most certainly a contributor and for some who may not exercise like you, or consume an appropriate level of protein this research may show that those taking the drug need to focus on a more protein right diet.