Pure myth, salt is needed for the body.
No question. Consuming a good salt vs table salt does make a difference. Salt definitely causes the blood pressure to rise. Like I said, I know this from decades of personal experience. Celtic sea salt doesn't affect 'me' nearly as much as table salt.
The theory behind lowering salt to reduce blood pressure is: Blood pressure is lower when people are dehydrated.
They are saying you should live your life dehydrated to keep your blood pressure down.
Dehydration has its own set of problems. There has to be a better solution.