Hi clo,
You are right. It really is a cultural decision. It isn't as if every post by a banned poster is no good. But nor do I want to argue with folks just for the sake of arguing. It's not that I find someone's argument disagreeable. It's that once a person starts to base their arguments on facts that are manifestly false, or that they are careless of the truth, I don't know how I am meant to trust what they write any more.
There are places for unsubstantiated rants. I don't mind the fact that people choose that mode of expression. But this isn't the thing I intended this board to be about.
If folks prefer the ranting kinds of posts, there are plenty of places to go to find them.
As it happens, in maybe six years of moderating, I've given up on - I think - three posters. Not a bad record. I don't delete posts (except from banned folks). I let people post until it is clear they are not going to accommodate the moderator's advice.