Let me try to explain this, one last time.

When I encountered this situation, I saw two posters making trolling posts. Given the choice of banning both or warning both (both choices being equally valid), I decided to be lenient, and made a post to warn both of them. While I was doing so, another Moderator banned one of the two posters I was going to warn. I chose to amend my decision and follow suit with my fellow Moderator, and banned the other poster. This was the most fair option, because punishing one and not the other would have been biased. And our goal is to be fair.

That’s it.