In addition the comments on the front page are moderated. Some people feel that anything that they type must appear.
If you were having problems (for example) running the software on Vista - you are instructed to post problems or ask for help in the forums. Perhaps the moderator felt your comment belonged in the forums.
When you write a letter to the editor of a newspaper - some letters are never published, and others are edited before publishing. Just because you are commenting on a website, doesn't mean your comment will actually appear. There is no guarantee your comments will be published - only an assumption on your behalf.