No salt is not the main cause of obesity, but it does help contribute to it.
The main cause of obesity is the inability to control your food intake.
Snacking on healthy foods is not bad, but eating the amount for a meal as a snack throughout the day is.
I know the half a cup serving isn’t enough for majority of people. Serving sizes are based on caloric intake v activity. But most people don’t feel as though they get enough to eat based on caloric intake. 3000 calories a day may be fine for some people, but not everyone. Once again it’s calories versus activity. And society as a whole has become pretty lazy.