The major thing which is troubling about groups that present themselves keeping Torah but are idolaters-they is they worship their tzadik-is the hypocrisy aspect of it. The way I see it is that people can either try to keep the laws of the Torah which includes the second of the Ten Commandments "Thou shalt have no other gods before Me" or not claim that are trying to keeping Torah and trying to get money constantly from secular Jews to support their supposedly superior life style.

But you can't say this openly nowadays because it is obvious. People only want to hear something complex because of "Physics Envy." The fact that the truth is sometimes obvious does not matter. People want it t be complicated.

I am not sure however how far to go with this. There still remains the question that some of the people like Reb Nachman were tzadikim. The fact that they are also objects of idol worship does not invalidate that. But it does invalidate the groups that do the idolatry.

The Gra put the whole group [everything, not just Breslov] into excommunication which has legal implications.For example one is not allowed to pray in a minyan with them. Nor learn Torah from them. Not teach them Torah. Nor sit within four yards of them. The laws differ between חרם and נידוי. [Cherem and Nidui] "Cherem" can be translated as excommunication. "Niduy "is rebuke. The category the Gra put them into was חרם excommunication.

An example of חרם is what you find in the Gemara with Rabbi Eliezer. Though he was clearly a tzadik still the excommunication had halachic validity as he he himself knew and acted accordingly He did not deny the validity of the excommunication.

There is a question how far to go with this. To what extent is it even possible?

Furthermore I want to point out that I would not be mentioning this if not for the damage these groups cause. That is what I suggest is that the excommunication only reflects an objective reality that is there regardless of the excommunication. Not that the Cherem made them bad but they were bad before the cherem. The cherem only addresses the issue of how to act.

The best way to deal with this issue is to learn the basic subject of idolatry from the Gemara itself. That is mainly the Gemara in Sanhedrin on page 63. Learning that sugia in depth helped me come to clarity about this issue.

Outside of that Gemara it is possible to see the problem by the ugliness of their deeds. That is hard to explain. Mainly I mean that it is one ugly deed then that is just a "קושיא" a question. But by that prevalence  of ugly deeds it is possible to draw a conclusion that there is something about the energy that produces ugly deeds as predictable as the setting of the sun and just as often. And it is not bad deeds. Bad deeds are just wickedness. But there is something ugly about their deeds that is not exactly wicked. It is just that their actions are ugly. There is something wrong with them that you hand put your finger on exactly. And it is not just as it applies to one person of the other. Since it is often and constant and perennial you can conclude that there is some ugly energy producing these ugly people and ugly deeds.