It's not a matter of agreement, it's a violation of federal labor law for people not involved in the service from taking any portion of a tip. Tony Xu was taking parts of tips to reduce the company's wage commitments.
And my point was in various US states this is apparently legal to do if you trade Tony Xu for some restaurant owner and DD drivers for servers. So why has it been Ok for restaurants to do this? Does a different law apply to DD situation?
You say Tony was taking tips, Tony says he was grossing up workers who don't earn enough tips. The whole outrage is people want to pay less than the job is worth and then blame Tony for it from his side.
No, the model was to pay $X unless there's a tip, in which case Tony takes it and pays $X-$tip (unless the tip is over 100%?). Management is taking tips, which is hella illegal and has been (to varying degrees) for quite some time, certainly since before DD existed. tl;dr: wage+tips, not wage-tips.