It's not (exclusively) earned income that they want the "rich" paying their "fair share" of taxes . . . it's the wealth that they want to tax, based on a snapshot in time. The value of a home, or a share of stock, land, a rare automobile, the wine in the cellar, jewelry, the items that represent individual net worth.
Now, mind you, "rich" is never defined, nor is what a "fair share" would be . . . which simply allows the allegation to be perpetually used whenever desired to create an "us vs them" division within the populace, which is the entire point of the exercise. Take more from them to give to me.
