People, right or wrong, are entitled to their opinions.
If someone has a different opinion to you, you can have a friendly debate but as soon as it is no longer "friendly" it needs to stop.
Unfortunately, when some get hot under the collar, they feel the need to have the "last word" thereby (in their opinion) having proved their point and won.
These last words are usually petty/childish/snarky, having become arrogrant, insulting and are degrading to both of the posters. At this point a moderator will step in. What action the mods take is entirely up to their discretion.
This is a privately owned forum and they can make whatever rules they want! If you should want to make a change you are free to make any suggestions you would like. If "they" do not agree it is their right and privilege.
As Cooking Goddess pointed out, when you registered the rules are clearly stated. Even on the "Back Porch" there are limitations.