It's not even being anal, if I was telling someone I love tangerines and they tell me that's awesome, oranges are really good for you... I'd be a little baffled I suppose.
I really love how the author complains about the other missing the bigger picture, when there's a bigger picture they themselves are oblivious to: the ideas in your head are really awesome and all, but if you don't learn how to use language properly to communicate them then they're useless to everyone else.
"calm controlled behavior: the ability to behave in a controlled and calm way even in a difficult or stressful situation"
The pedant was able to create new habits that allowed him to be controlled and stick to a routine even in the presence of stimuli that would cause him to no longer exibit this control.
The term consistency, when applied to human behavior, is almost always a form of discipline -- except when it comes to certain bodily functions... like heartbeat or going to the bathroom.
When we need to use discipline, we need to use self control in order to fight against a natural instinct that's more pleasurable. Of course, there's always a combination of the 2 that's needed, but habits generally rely on learning new behaviors that become natural.
To be clearer -- consistency and discipline aren't exactly the same, but you get consistency in human behavior via discipline.
Technically the original poster was correct. What the pedant did required discipline. The pedant saying that it wasn't discipline was actually not even technically correct. By attempting to be pedantic he actually said something that wasn't even technically true.
Now what you're saying is that there is some other behavior that might be implied by the term discipline, which is a prolonged test of willpower. This technically is not in any definition of discipline I've seen.
I'd argue that if you're going to be a pedant, you at least need to be right.