You may not understand that sentence for cultural reasons because even for someone familiar with how tipping works in the US they might not understand the sentence either because it is the very definition of "gaslighting"[1].
It's referring to their practice of boosting your per-delivery earnings to $6.85 if the customer does not tip you enough to meet that minimum payout.
A term you'll often hear wrt paying back creditors/investors/options, making them whole.