None of the reasons why enforcing “clear borders” is good for coerced children carry over in any way to children who are in consensual relationships with their parents. On the contrary, enforcing fixed borders and bottom lines is irrational and coercive, and sabotages the very means by which such children remain happy.
Punishment has a very high risk of destroying not only the desire, but also the ability to learn.
When one is the victim of a great injustice, there is a tremendous temptation to define oneself, and one’s life, at least partly in terms of this injustice. The victim mentality is a terrible mistake because it sabotages the vital process of learning how to have a happy life, solving problems as you go along.
Adults tend to hold entrenched, irrational ideas, which no amount of reason on the child’s part will shift.