I think what is being said it that salt, as a flavor enhancement, is personal, an individual taste for an individual person. Rather than adding salt in the preparation process, where the amount of salt added, may in fact be too much for some, not enough for others, leave it up to the individual dining patron to salt to taste at the table.
I know there are many times in restaurants where the salt level in the prepared food is too much for my tastes. And one can not remove salt, but one can add it if needed. To me, it is similar to getting toast, and having it buttered before it comes to the table.

Never have figured that one out.