Everybody who voted on the bill was told right before they voted that it would lead to people being dropped from their plans: http://youtu.be/7kEDgyshwrc?t=2m7s
That's not reason alone to call the ACA a bad bill, but the lawmakers had to know that was a possibility at least. And therefore they probably shouldn't have sold it to the public by guaranteeing that they could hold onto their old plans if they wanted. That's a fairly significant piece of misleading information.