The Da'wah of let's-mix-everything-together is dangerous.
The Messenger of Allaah - sallallahu alayhi wa sallam -, his Companions, radiyallahu anhum, and those who followed them in goodness, especially in the Two Following Generations, never did it that way.
Mix-up Da'wah has never been successful. It will not be successful still.
Imagine a sitting comprising of those who curse the Sahabah, those who believe in uprisings, those who believe in veneration of their teachers, those who believe in protest, those who believe....and a person of Sunnah sits there to co-operate with them. This is a major flaw in the manhaj Sunnah, a major flaw, no doubt about that.
If they force one another on a friendship today, it is either they adopt one of the heresies as the uniting factor, or those who can't bear it again quit tomorrow (with bruises on Aqeedah and proper understanding).
May Allaah rectify all of us and open the eyes of those who are still blind to this.
The truth is the most powerful entity, it supercedes all personalities, locations, bearings and inclinations.
