This is philosophically interesting. If you take this to the extreme, employees and children should question the legitimacy of every "order" they get from employers/parents.
You already know my position that there exists only One Law and that "lawmaking bodies" are merely political corruption. Not quite sure how to tackle Cultural orders...
Also, that guy makes it sound like this is always a binary. Sometimes you can have an order and a conscience, and you choose an action that is in agreement with both.
He is a bit manic about it, but when you see it from an OCD perspective it gets unbearable to see how people violate each other justifying themselves with opinions.
Blindly following orders definitely is a big problem, especially in times of overreach by authorities. Refusing all orders seems to me to be another mistake.
For example the rule of what side of the road to drive. Pour conscience probably tells you nothing about it, but your ideas may suggest that some places other side is better.
Also, there could be stuff you simply don't understand, but the law is easy to follow. Speed limit may look way too low, but there is a hidden problem in the area for example.