One reason to obey the excommunication of the Gra is that children need a wholesome environment that you just can not find anywhere outside of the straight Litvak world. You might be inspired by Rav Nachman and that is fine. But there is a difference between what you can learn and the environment in which children ought to be raised
[Anyway my opinion is that Rav Nahman himself was not an object of that "herem" because that was more specific than most people realize. To see this you ought to look up the actual language of the herem which I found in one book that contained the actual language plus the testimonies that were collected in Villna before the publication of the herem.
It should not matter what the herd thinks. What should matter is what is objectively true
