What kind of organizations?
Compared to the Moonies or the Church of Christ, I'd say JW's are not as bad.
Compared to a Methodist or Presbyterian church, JW's are far worse. Mainstream Christian religions, in general, don't hold themselves apart from all the others or bash the others. For most what's important is believing in Jesus as saviour and being baptized, the rest are details left to interpret and are not essential. So the what sounds right to you, as far as the non-essential details determines which church you attend or don't. JW's, oth, have a strict set of rules you have to live by or God will not accept you, thus the term "truth" "true Christians", etc. But that truth changes frequently, and it's not up to the individual conscience to believe that's true or reject it. You either believe it or you get kicked out. Most Christian churches will not kick you out because you hold a different understanding of something and talk about it with other members. That's why you see members of one church visiting other churches, or different denominations working together on charity projects, at least they do where I live. Can you even imagine JW's doing that?
I think they're worse because of their seperateness, their patent on "truth", their disdain of other Christians, and how they dictate what others believe and keep their members like children not able to determine for themselves what's right and wrong according to the Bible. They follow men, not Christ, who they should be following if they're Christians.