From the BBB's FAQ...
If your funding comes from businesses, how can you be fair to the consumer? The purpose of the BBB system is not to act as an advocate for businesses or consumers, but to act as a mutually trusted intermediary to resolve disputes, to facilitate communication, and to provide Reliability Reports on companies. Businesses have supported the BBB for over 80 years because an ethical, self-regulated marketplace is in everyone's best interest.
I have no problem with the "intermediary" aspect as they do seem to help in some situations. Not every complaint is legitimate. I am sure that the people who think that the BBB is great had a resolution in their favor, and the people who think that the BBB is only for the business didn't have a resolution in their favor. I also don't feel that having to "prove" your complaint is a RipOff.
Now, I do feel that their is a "problem" is with their ratings. Even though they are a "non-profit" organization they need to pay their overhead. How do they pay for it? By having companies pay for membership. Whether related or not. There are many times when I have seen a company that is not a member of the BBB have no complaints and have a B-D rating. Yet a company that is a member and has dozens of unresolved complaints has an A rating. This can make it appear(true or not) that by paying for a membership you are paying to get a better rating.
Just take as comparison Consumer Reports (CR). They take no payments or advertising from compaines. How many complaints about them and their ratings have you seen?
Perhaps if the OP would give the specifics of their case it would help explain their position.