You don't know what the waiter's situation is, so how can we presume to know better than they do? Are you sure the people who are choosing to work for these services would agree?
Secondly, you have the option of giving a nice tip. I suspect they'd prefer that over not renting their Airbnb or whatever service they're offering.
Read the article. They say they don't take tips, but the relationship between tip and actual pay is so arcane, that driver payment is higher when you tip $1 than when you tip $8. Obviously they don't know what the algorithm is, but it's not as simple as "we'll pay the driver the delivery fee and keep the service charge, and you can give them something on top of that". It's more like "we'll take as much of the tip, the delivery fee and the service charge as we possibly can get away with, even though that's completely in contradiction to what the purchaser thinks their doing".
Secondly, you have the option of giving a nice tip. I suspect they'd prefer that over not renting their Airbnb or whatever service they're offering.