I do some pretty serious backcountry trekking in the summer. You can feel when your electrolytes are low after several hours, the signs aren’t particularly subtle. Fortunately, you can slam a few grams of electrolytes and you’re back to normal in a matter of minutes.
Our bodies can handle it, humans largely developed in regions where electrolyte depletion was a risk. The amount of salt you have to consume to regulate your electrolytes in environments with high electrolyte loss dwarf what you are going to consume in typical food, processed or not. The idea that the average human is hyper-sensitive to consuming too much salt is preposterous. Even animals gravitate toward salt licks.
However blaming salt was quick and easy so that’s what the people with money did.
Historically speaking salt has been such a scarce and valuable resource. I have read accounts how in the balkans people would resort to selling kids to slavery just so the family could have enough salt to survive (sacrificing one kid to save the rest).
When I started reading about how salt was bad for you it never made any sense.
Source: https://www.nhs.uk/live-well/eat-well/food-types/salt-in-you...
For iron, that trade would have mostly been in tools. For salt the only reason is that salt is a vital nutrient and if you can't get enough of it, you die. (Though I think it's worth observing that iron is a vital nutrient too.)
The history actually runs in the other direction - step one was that someone decided that salt was bad, and step two was that a bunch of dietary standards were created to express the revealed truth that salt was bad. The demonization is the beginning of the process and was done for its own sake.
Most people don't know this. It is a common prank to convince people that don't know better to eat the fruit off the tree. As the other poster said, don't do that.
For example, humans have been eating olives for tens of thousands of years. Olives contain and require prodigious amounts of salt to taste good, usually in the form of seawater.