My physiology professor explained it to me years ago. There's two reasons. First, we're told to cut salt not because salt is bad, but because we eat shitty food filled with salt. Telling people to avoid salt is easier than telling them to avoid bad foods.
Yeah, that's what I did. Avoided salt and went for the carbs instead. Now I've both high blood pressure AND am type 2. Worked great. Protein, often high in salt, or carbs. Choose your poison.