The other problem is that it is possibly to give offence inadvertently because when you write something, it is to say the obvious, not spoken, so that tone of voice and the extra meaning that spoken words give, is missing when written down
For example, if i say to someone 'You are an idiot' it can be said when someone is telling something really silly they have done and you are both laughing about it and the phrase has no pejorative meaning at all, but you can also say it with a voice of anger, contempt and disgust, which gives the phrase a really offensive meaning - and everything in between. None of this comes over when it is just written down.
Some people use being upset and taking offence as a tactical weapon to put down other people where they have failed to do it by honest debate.
I must say that being expected to have read a whole thread before posting , is fine when it is 4 or 5 pages but when it is 20 pages or more, is one really expected to read the lot? I find it very helpful to have a voices of dissent pointing out something, usually practical, on a thread every couple of pages.