My house, my rules. I don’t guarantee that your comment will be posted; this is my blog, which I pay for, and I may choose not to post a particular comment for any reason. I don’t guarantee that offensive comments won’t appear on my blog; in the first place, I don’t monitor the comments constantly, and in the second place, I may allow people to express offensive views in an otherwise civil way if I think there’s potential for useful dialog. I do guarantee that I won’t edit your comments to make you look silly; I edit comments only with the poster’s consent. I’ll also delete any comment if the poster requests it.
I don’t guarantee that I’ll moderate comments by a consistent standard; in fact, I guarantee that I’ll moderate them by a variable standard. Whether I consider your comment too offensive to post may depend on the context of the thread you’re posting in (an argument against Christianity is more welcome in a thread of theological discussion than in a prayer request thread). I’m also harder on anonymous comments than on comments from people with either real names or established pseudonymous identities.
Again, my house, my rules.