I hear you :-) I have only been on SteemIt a few days and have seen it over and over on posts where it just doesn't seem justified as you mentioned. It's one of those internet things that just won't go away - a carryover from the past days of MySpace.
On posts that really interest me, I go through and read the comments from other users as well. It helps me follow through networks of other good contributors and the "noisy" replies do get annoying. Not an overreaction - I'm *sure a lot of people feel your frustration.
Now I already think about leaving such comments with no reply at all. At first I thought it would be rude, but now I already think that spamming me is rude
It's a tough call on the response though. I have seen a few posts where the author got into a back/forth reply war and it went ugly fast. Then you get a bad vibe for the author as well, who was not in the wrong to begin with, but just reach a point and snapped.
Did the same once. Had to mute that guy as a result. I'm here not for spoiling my mood after all