Fat isn't bad per se. Excessive fat consumption however is as are saturated fats.
Peanuts mostly contain unsaturated fats. Peanut butter though might contain all sorts of other ingredients that are rich in saturated fats (like some plant oils).
The problem with salt is that in general Western diets already tend to use too much salt and too much salt can lead to an increase in blood pressure, which ultimately if untreated can lead to heart attacks and strokes.
Peanuts mostly contain unsaturated fats. Peanut butter though might contain all sorts of other ingredients that are rich in saturated fats (like some plant oils).
The problem with salt is that in general Western diets already tend to use too much salt and too much salt can lead to an increase in blood pressure, which ultimately if untreated can lead to heart attacks and strokes.