Popa:
Sam’s point there was that if an apikorus believes that he is not an apikorus then his status as an apikorus should have no practical ramifications for us. You pointed out there, that if the reason why he believes that he is not an apikorus is that he is following a shita which you believe to be out of bounds, then he would be suspect of doing so in all areas of halacha and cannot be trusted at all. In other words his misguidedness is relevant on a practical level.
Here though, the Neturei Karta folk believe that they are doing the Ratzon Hashem. You can point out that they are misguided and you can try to convince them to change, but I don’t see how you can know that they hate Hashem. They might love Hashem more than anyone here, but they just don’t know how to properly show it. Unless you are asserting that they are lying to themselves, but I don;t know how you could prove that either. Just to be clear, I am not defending Neturei Karta in any way shape or form; I’m just pointing out that it does not necessarily follow from their actions that they hate Hashem, and if the issue is whether they hate Hashem, it is irrelevant whether they are right or wrong.