We leave a lot of topics open until it is clear that it is not going to stay civil.
We moderate to keep things suitable for all ages, to keep things from becoming inflammatory and to follow the rules.
Some topics cannot stay civil no matter how much moderation time is given to it. It doesn't matter the subject. It could be politics, it could be the color of a feather, it could be too much personal info, it could be a cat story.
The Staff doesn't moderate based on personal feelings. Rob is very clear to us that when moderating, our personal feelings are left at the door and we follow certain and strict guidelines as to how and what we moderate.
When we moderate, we do not explain everything to everyone. Unless it is a totally obvious "duh" type of edit or closure, we contact the OP of the thread and anyone who contributed to the moderation. It is simply no one else's business and we will not discuss it.