It was 25%. But a 25% tip on a $20 order really isn't that impressive. The driver does much the same amount of work as for a $100 order.
Income inequality does make it possible to hire gig-workers to run increasingly trivial errands for us, and the structures that enable that do make it possible to treat those gig-workers like shit. That does not mean you should. If you're going to order small, you should tip big and I don't think that is remotely controversial?