I'm a bit skeptical of an organisation that recommends eating lots of carbs and margarine. Is there good scientific evidence that salt is dangerous? A priori I'

I'm a bit skeptical of an organisation that recommends eating lots of carbs and margarine. Is there good scientific evidence that salt is dangerous? A priori I'd find that strange, because our kidneys are good at filtering out salt, so why would the body have any trouble with salt as long as you drink enough water?