When I first came to Israel I had the unfortunate experience of sitting in jail during Passover with quite a few members of Neturei Karta. (There was a demonstration and I was inadvertently rounded up.) I got to know their views upfront and very close. I disassociated myself from them very quickly. Like any movement they have points in which they are correct, but they then use those few points to totally distort. G-d forgive me for making this comparison, but sometimes I feel like they are our Taliban and Al-Qeda. They are perverted extremists. While direct murder is not on their agenda, since murder is just not part of Jewish tradition, however I do blame them for killing Jews inadvertently by give aid and comfort to our active enemy.
They are the opposite side of a poisonous coin that unfortunately exists in Israel. Just after the 6 day war I met a guy who was a scout in the Negev. He grew up on a SHomer Hatzair Kibbutz where Marxism supplanted Judaism. He knew absolutley nothing about Judaism and called himself an Israeli not a Jew. Despite all the miracles during the war, he said that there was one major tragedy. I said I didn't recall one. He responded,"it was a tragedy that Jordanian bombers weren't able to blast to hell Meah Shearim and Beit Yisroel (the neighborhoods where almost all Neturei Karta live)." The Neturei Karta member would have responded that it was a pity that the SYrians weren't able to destroy his kibbutz. Both attitudes are the extreme of the extreme, and to our shame they exist. G-d only knows how much we try actively and through prayer to unite all Jews.