The concept of חרם (or excommunication) is not well understood. People tend to this of it as an option whether to pay attention to it or not. But in fact it is a legitimate halachic category. It has a regular classification of an איסר נדר. That is if you say about a sheep or goat "הרי זה קרבן"["This is dedicated as a sacrifice in the Temple"] it gets a classification of being sanctified for the Temple in Jerusalem and one is not allowed to use it for any mundane purpose. It becomes a חפצא של אסיר an object that is forbidden to use. The idea of a חרם gets its validity from this same idea. You can see this in the laws of oaths in the Rambam. In the commentaries on the Rambam there is a debate whether a נידוי or חרם come from the category of איסר נדר or איסר שבועה. But there is no doubt that one that transgresses it is considered as if he transgressed a נדר או שבועה and that is a לאו דאורייתא (prohibition from the Torah itself).

When the Gra made a חרם he was not inventing a halachic category but using one that already existed. The reason he wrote elsewhere. The Gra held the teachings of hasidim are from the Sitra Achra and that its energies are fallen energies--miracles given to them like the miracles done by the Golden Calf. Miracles and powers of the Dark Side.

So why is it ignored. The institutions that would normally be following the Gra were infiltrated and taken over. That is Lithuanian yeshivas. [And this also explains what many people wonder about --why are Lithuanian yeshivas  corrupt? Well now you know.]

The answer to all of this is simple. To start paying attention to what the Gra said. It could not be more simple.

The only way now is to be for or against. There is no middle road. I though before I could find one but I see now that was a failing strategy.