One of the criticisms that the Watchtower has dealt with over the years is that it is not a "Christian" organization. I think the leaders became sensitive to the charge and decided to include the name "Christian" as a simple refutation. In the last few years, the Watchtower has put more emphasis on Christ even including his name in the assembly themes. But it is difficult for the Watchtower to overcome the inference because many of the attributes of Christ as savior, judge, prophet, etc. are bestowed upon the FDS by its members.
Wednesday, many trinitarians teach that the trinity doctrine is the "foundation of Christian belief." Therefore, they condemn any who hold to the unitarian doctrine as "unchristian." But the persistant rejection of the trinity by some Christian groups down through history give their arguments worthiness of consideration. It's to be noted that when the controversy tore the church apart in the 4th century prominent members in the church including bishops and emperors supported the Arian position. It took years of conflict and slaughter before the trinity emerged as the "orthodox" view.