THE EXACT REASON: The short answer is that we don't know. It isn't necessarily a swear word. Comment moderation is a very complex and not entirely accurate algorithm. The software takes its best guess. There's no way you and I can know the specific reason a comment is filtered. Maybe you used a word that sounded to the algorithms like a particular pharmaceudical that people spam forums with, or you used the word "gambling" in a way an algorithm thinks might be a pitch for online gambling sites. The system necessarily uses adaptive, fuzzy logic, so there's no way to tell which of a gazillion rules was triggered. It's not just a simple set of linear rules, which could easily be defeated by spammers. We also didn't write the rules and can't edit them except for a few basic settings.
THE SOLUTION: There's no solution that guarantees it won't happen. If your comment is held for moderation, wait for Dr. Farrell to approve it. He checks routinely. If your comment or post is immediately filtered as "inappropriate", and it doesn't contain anything you think should trigger that, you can try posting again in a few minutes. If it contains a borderline word like "viagra", you can try omitting that. There's no procedure to white list certain words or phrases or certain users. The filter is either on for everyone or off for everyone. If we turn it off, you're going to see a lot more spam and profanity, and the community becomes unmanageable.
SECURITY IS A TRADEOFF: Unfortunately, we can't require locks on all the doors - just none of the doors we prefer to use. So, to secure the site, some comments might have to wait a day until we being approved in that day's round of moderated comments. Or your post might get wrongly flagged as inappropriate, and we won't know why or be able to do much about. It's the risk we take with putting up an intelligent spam barrier that is not outwitted with a simple rope ladder.
COMMENTS ARE FREE: Keep in mind, comments are a free feature. They're not part of paid membership, as evidenced by the fact they're open to everyone who registers at no charge. We don't guarantee that anyone is entitled to comment or post without ever having it moderated, and we don't promise to provide a reason for moderation (we'd be making it up, if we did). The reason we use an electronic system for moderation flagging is that it's just too opaque for us to operate manually across thousands of comments. If your comment goes to moderation, we appreciate your patience, and it will most likely be approved in the next round of comment approvals, which usually happens in a day or so.