Our forum managed to be a fine place without any such rules.

It is just the creeping in of more and more restrictions over the years that have almost ruined it.

Such things are fine - at the start-up of any such forum. It looks to me that this example is going to be a fine one for you and all of those who do not like and can only accept our forum on their their terms, which they feel they have some right to impose on everyone else. And also feel they have some right - as you to do to publicly suggest that other posters be banned.

Had such rules been in force at the start-up of our forum and posters always contributed on that basis - fine. But to introduce such things - or impose any further posting restrictions at any later period is to move the goal posts.