I know that this isn't something that should drive me crazy, but it is. I've heard the phrase for decades, but it always draws the weirdest mental images.
We don't get salt from tables! Salt is salt. Yes, it can come in many interesting colors. (Pink for instance) But is there a special mine out there that has a big sign on it that says "FOR TABLE USE ONLY! YOU CANNOT SEASON YOUR FOOD UNLESS THIS SALT IS IN A FANCY SHAKER SITTING ON THE TABLE!"
Epsom's salt aside, of course.