Those promos are offered by Disney resorts, on rooms they own, to guests who are paying them for the use of the rooms they own.
When you book with your points, you are booking member-owned room inventory. You don't pay any money to Disney resorts, as you are not using their rooms. Therefore there's no reason for them to give you free food.
If you're a member already, do your math with the different promos and you'll see booking with points is still hundreds of $s cheaper than taking advantage of any of the promos.
If you're renting points, you will have to rent the points at $12 or higher to even match the cost of the promos.