Walk the curve means the curvy line that goes between right and wrong. The curve line which is the grey area between right and wrong. As in for some people doing wrong may seem wrong but its not wrong. But for others it would be wrong.
To be free and not a pretender... you have to not be scared to look like a failure! You must not be scared to look like an outcast... and you must do what you believe is right... not what others want you to believe is right.
To walk the curve!
For example a person who does not get drunk and is completly sobra after 3 pints could drive and not be affected and another person could be drunk as a skunk... this is a grey area. A curvy line. It would not be wrong for the sobra 3 pints person to drive, but completly wrong for most to drive. So to walk the curve is to find your own right and wrong. And not be defined by others, to realise you are an individual.
I never know if that guy is good or bad in this film... Nah he's just walking the curve.