A while ago Who You? posted a piece from the Toronto Globe and Mail questioning whether Ismailis were Muslim. Here is the response to Tarek Fatah, the author of the original piece. The basic response is the same as it was in the original article, the Ismailis aren't Muslim because the majority of [unnamed] scholars hold that that they aren't because of various [unnamed] beliefs and practices. Who are these scholars? What is their background? What is the basis of their argument?
Important point, the Ismailis were recognized as the Caliphs of the Muslim community by a large segment of the ummah in the 10th and 11th centuries when the Fatimid Empire held sway. The Abbassids may have launched the Black Legend, but it's been so thoroughly discredited by scholarship of Muslim (Qadi Numan, Farhad Daftary) and non-Muslim (W. Ivanow, Michael Brett, Heinz Halm) authors it would sadden me greatly if any thinking Muslim still believed it. However, that's why it's important to know sources. Don't forget Al-Azhar, the center of Sunni learning, is an Ismaili institution. Ignorance is one thing, ignorance that devalues the Islamic tradition and attempts to destroy it is unforgivable.