I think the OP is a genuine question, its not insulting, it's not demeaning, it' simply asking what exactly can you say to someone who doesn't get what you are saying. Well, what do you say?
it's probably easy enough face to face, where you can judge, unless you have difficulties doing so, body language, tone of voice, facial expressions but when it's the written word it's so much more difficult. Many people as we've seen project their own feelings onto another, "wow they are really angry and/or upset", 'gosh this person is being really offensive" etc etc. The truth is much more prosaic, only the person writing knows the emotion the post is written with, so many posts start with the assumption that the other person is 'upset', this never bodes well for a civil conversation. Others start posts with the idea that they are right the other person is necessarily wrong, well often they are but they think they are right too.
Then we get those posters who think something someone said is actually something else. I have a poster on here who thinks I said his kids were on drugs, he's never forgiven me for it and slates me every chance he gets, despite the fact I didn't know he had children and I didn't say they were on drugs ( this has gone on for a few years now lol) so people carrying grudges stir things up, goading others and making sure that things go downhill quickly. Rather spiteful I always think.
Another 'type' is those who tried something for a little while, didn't like it or it didn't work out
for them so that they then post at every opportunity that this thing they can't do doesn't work, is rubbish and is all fairy tale stuff thus annoying those who manage to make it work fine quite annoyed. See all threads on kata.
Allied to the above is those who watch videos and think styles they've never tried are rubbish because videos are the gold standard of martial arts and if it doesn't look right on a video it's pants. it doesn't occur to them that the videos are made by numpties and even the people from their own style shake their heads at them. So again this annoys those who make those styles work perfectly well for obvious reasons.
We have too those who are keen to let us know how tough they are, they learnt everything on 'the street', they've been there, done it, got the t shirt and the brain damage to prove it, no-one in a fancy Gi is going to tell them that traditional styles actually work.
We do have traditionalists who argue among themselves of course as well as those who think they know better than a professional ie telling a police officer how the job is done. We have people who really think they have to disagree rather than ignore because saying nothing is the easy way out and letting a myth or misconception stand because it might upset someone is better than having a potential argument. See threads about domestic abuse for examples of this. Sometimes the truth isn't comfortable and does cause arguments but better people know what domestic abuse is and how to deal with it than let ignorance cause more victims.
I believe in being honest despite people thinking that honesty is just being argumentative, I will say what I think otherwise why bother? You would not survive long in Yorkshire if you mince your words, you'd be seen as mealy mouthed. 'I spek as I find' is the watch word here. it's a harsh living in this county and people don't have much time for those who babble or bluster, they call a spade a bloody shovel and if thee canna bide it, thee can allus shun mi.