No one can obey a would-be authority that doesn't give self-consistent orders. One may try, but there's no pleasing it. Life is an endless and futile struggle with double binds and shifting goalposts.
And what is discipline but consistency in practise? And doesn't consistency boil down to picking a purpose/direction and sticking to it?
John Walker's parents were too "open minded" to open their mind to any sort of concrete, definable purpose. What little consistency their lives had was doubtless force of habit. (I'm saying this based on people I've known who I'm sure are the same type. Yes, I'm stereotyping. So sue me.) Their kid didn't have the benefit of their force of habit, so he went off on a wilder tangential trajectory than they ever could.