Carolyn, read the history of that organization to find the founders. I posted that he did join in 1867 and at that time it was not bad. They were doing good things for the widows and orphans. It was later that some folks donned the hood to do the bad deeds and no one knows whether those first acts were the real members or not. It was then that NBF quit and tried to get it disbanded. At first, just being a member did not mean you were a bad person. What the organization became later is not the fault of NBF. He tried to stop it.
As for not being perfect, there has only been one perfect man in our history and he didn't fight in the war for either side. During NBF's lifetime he was a slave trader, yes. It was an honest profession at that time. He was one of the better ones according to many eyewitness accounts. That is to say he treated the slave with as much respect as society would allow at that time.
What you say about the net is true. It is a good resource, but a follow up is needed for anything you find on the net. If you find the same FACT in 10 different places on the net, it does not make it true. Always follow up with good source material.