Because that church, Pergamum, represents Eastern Orthodoxy, just as Thyatira represents Roman Catholicism, Sardis the (now) fallen liberal 1517 Protestants such as the PCUSA, Philadelphia the revivals of 1776-1900 approx, Laodicea the rich people of the West who know nothing of the reseves of Christendom that they are living off of, and battening on, and think they have gone beyond Christianity.
Bah! Muslims will have them all for lunch, will kill them sooner than they will me.