They are making a conscious decision to eat poorly/lack of exercise and cause their fatty liver disease. Just like somebody can make the conscious decision to not get vaccinated. Both are putting themselves at greater mortality rates because of their decisions.
Of course there are people who can have liver disease and still be in good metabolic health due to other outlier reasons. But if your poor diet choices or choice to be sedentary and not take care of yourself resulted in your poor health, how is that different than making a conscious decision to not get vaccinated?