In a restaurant
- The waiter is guaranteed normal minimum wage.
- The owner guarantees they will pay a minimum of <whatever waiter minimum wage is; less than normal minimum wage>
- The waiter gets tips from patrons, which generally brings them over normal minimum wage
- If the waiter's tips do not bring them above minimum wage, then the owner is required to pay them an amount that would bring them up to minimum wage.
With DD, it works more or less the same way, with the difference being that the minimums (upper and lower) are per delivery, not per hour.
If fact, odds are the DD deliverers are going to be worse off now, because DD isn't going to guarantee them a minimum amount; rather, they'll present "we pay you X + you get the tip which is likely around Y". And if the tip isn't enough, the deliverer winds up making less. Unlike before where they got the minimum.
My understanding is that DoorDash was doing the opposite: giving you a guaranteed wage and then subtracting the tips from that. It's as if a restaurant were paying you an hourly wage without tips, and then accepting tips on your behalf.
If a customer had tipped 100% of the guaranteed pay, do you think the deliverer would have seen any of that tip? Or would it all have counted against the guaranteed pay?
Waiters don't pay the restaurant back if they go over minimum wage. So, no, it's emphatically not the same way it works.
And even if it were, "it's legal to screw people!" is not a reasonable nor humane response to "people are getting screwed!".