That's the subject of another thread, if you want to start it. The fact remains that if someone isn't taught how to do a thing, and you look down on them for not being able to do it, that reflects poorly on you, not on them.

In that other thread, if you should feel moved to start it, you might consider what you're really trying to accomplish and whether teaching people to punch is the best way to do that. I spent a lot of time in karate learning how to punch, but that was part of the point of that style. If you're studying a style where the ability to punch is incidental, you might ask yourself whether there's a better way to achieve your goal.

proficient meant speed, power, accuracy and control. cracked someone's face meant lack of control, i.e. not proficient. when i punched someone, he or she will know that if they don't do something about it, i will take his/her head off. it will be delivered on target, on time, at the right amount of power, and if need be, can be stop within a cm of the target and i won't give away my balance. at least, that's the goal. and folks who practice with me will do the same. and not just about striking, but when grabbing, the uke's goal is to unbalance nage, without giving away uke's balance.