I had just typed out a smashing long post, then accidentally closed my browser tab...so I will save the civility protests and long explanations for another day.  Your proposed addition is mostly okay, and gives a good treatment to the question of how the word "terrorist" is applied to the organization.  I would add the FBI website, and the fact that it was one of the organizations on the FBI's terrorism task force watch list.  There are plenty of categories, too many probably, available to help direct readers interested in the topic of terrorism to this article.  Category:Terrorism in America is one of them; the one you just added (:Category:Organizations designated as terrorist by the U.S. government) is another.  There is a huge BLP concern with branding living ex members as terrorists, particularly unconvicted ones who deny the charge.  But again, this can all be handled by being cautious about what is said and how it is said.  Why don't I give this a quick edit tomorrow, here on the talk page, and if neither you nor others object I'll throw in my approval and we'll add the new subsection to the article page?  That's okay by me as long as it's kept neutral, and neither the category nor the text authoritative give Wikipedia's endorsement that they are terrorists... just that people have called them that.  Ciao.