Licensed physicians are mostly like politicians, their instructions are trickle-down from the higher-ups, the medical "authorities" who set policy, control what goes into the textbooks, etc. Its the same with clergy, police, lawyers or any other profession. That is just how humans' systems are structured.
Most people just want to live their lives and don't pay attention to any of this, until they suffer a medical incident, then they scramble for knowledge but by then it is usually too late, because these matters are not simple, and there is plenty of disinformation out there.
You might recall 2-3 years ago on V and G forum, I tried getting people wised up on the potassium thing, but it gained no traction. Such a simple concept, yet no interest.
The proper route for potassium to enter the body is the mouth, not the veins, that's why it made you piss so much.
12 ounces of orange juice contains about 500 mg. of potassium. Yet, there is some regulation that no supplement sold at your supplement stores can contain more than 99mg of potassium. Supposedly out of safety concerns. Yet, orange juice isn't banned and little kids drink it all the time. So, there's a good piece of circumstantial evidence that there is a war on health, the potassium battle is one of many. Nobody notices. They're too busy on things they deem more important, like shopping, sports, getting drunk, etc. When they have a health event, it is then and only then that you get to watch them scramble for knowledge.
Telling people to "avoid salt", cuts out a main source of iodine, which is iodized salt. And that advice gets listened to by, mostly elderly people who are already deficient. And instead, they get prescribed pharma meds. Its sooo totally - Darwin in Action.