It depends what you mean by NK. The old NK, under R Amrom, was 100% within yiddishkeit, and any difference one might have with them was the same as any difference of opinion within Torah. Now it’s my understanding that the majority of NK are still like that, but the Hirsch meshugo’im have so thoroughly besmirched their name that they just keep their head down and stick to what they believe is right.
Hirsch was simply a paid traitor to am yisroel. He’s just like Yishmoel ben Nesanya yimash shemo, and there is nothing more to be said about him. His followers are either traitors like him, or else crazy people who are not responsible for their actions. I think that is most of them; 50 or so unbalanced people whom he misled onto an evil path and they follow it like robots, without the mental capacity to reason their way off it.