Argue or discuss

Person A wrote something. Person B disagrees, and conclude that A is trying to do something bad. A is curious to know why would B think that way. There are two ways, one way is to ask or question B directly how did he come to his conclusion; another is to put forth the reasons of A to see whether B still have the same conclusion and think that A is trying to do something bad. A uses second way, but B see it as trying to argue and refuse to respond.

I think argue is personal and destructive. If it is not personal, but objective, I think the above is call discussion. Discussion is a good way for learning and communication.

Why do we need 0-100 scores in marking test? Why not just a pass and fail grade? Better and accurate feedbacks help people to learn.