There's nothing wrong with being new a sport. But there is something wrong with trying to act like you know a ton, when you don't bother to really try to learn. Offering uniformed opinions really just makes you look like an idiot. It doesn't matter what sport or topic.
If a new NFL fan was to pop into the NFL section and start declaring that Adrian Peterson is the greatest running back to have ever lived and its no content, then has no idea who Emmitt Smith, Walter Payton, Gale Sayers, or Jim Brown are... well, its pretty tough to take them seriously. If you don't know a lot, don't act like you do. Its simple. That's no different in real life than it is from a forum.