You're not factoring in denominated units (and subsequent rounding at send) and "dead change" being sent to the network to remove linkages in future tx's.
It was a simplified example explaining transactions in general. Remember: the issue we're discussing is the average user deanonymising themselves through inadvertently. Dead change and denominated units do not solve the problem when the user has 50 DRK in their account, they send 20.72368 DRK to pay for some dodgy item, and then because they have some crisis they empty their wallet and deposit the entire remaining 29.27632 DRK on an exchange. Normal actions resulting in unavoidable and unwitting deanonymisation.