I'd like to say, that every site has bias one way or another. Even if you really don't think you have bias, you do, even I do.
The key isn't to try and eliminate it, but to understand it and try to avoid making your personal taste and things you tend to be more bias toward get in the way of honest discussion. In a place like a fan forum, you don't have to worry about that as much as just trying to be respectful of one another's opinions.
For example, even though Disney has played a much bigger role in my life, their recent decisions have made me jump on the Uni train for the most part. I love them both to death (Disney probably a little more), but Disney hasn't wowed me the way Universal has in a while so naturally as of now I've been a bit harsher towards them. Combine that with the fact that my love for Uni more recently has been a breath of fresh air, it makes a difference. It's not because I hate them, but when they're making their track record worse it's going to be a lot harder to impress me. Universal and Disney could make the same product and as of now I could sincerely say, due to Uni's recent track record I'd be a lot less skeptical on the quality.
I'm biased against Avatar, so naturally I'm going to be harder to wow with that land. So I recognize that, and admit it honestly when taking part in discussion and move on. That's all you have to do and it makes you better than the people who get on your nerves for dumping on Universal every time something new comes out.