I dont see why "Cumhuriyet" is not a relaiable source. Certainly it has a secularist bias, but it is not suprising that it is a secularist newspaper that challanges Gulen. About Hulki Cevizoglu,  your argument doesnt make sense; "what does "every knower knows" mean? Besides, Hulki Cevizolu is hardly the only respected journalist to  accuse him. About Veren, are you denying that he was the right hand man of Gulen and is it surprising that he is denounced once he breaks away from the group.
2) Im planning to rewrite the article, my plan is to add the actual events and then provide the views of supporters and adverseries of Gulen on the event.  think we can really get a good article out of this, so I would appreciate if you could help me with the Gulen's supporters views of the events. Here are the events that I plan to add
a) his anticomunist activities before 1980
b) the rise of the movement through educational activities
c) Gulen's political connections
d) the tape incident and the ensuing legal battle, gulen's move to the US
e) the nurettin veren controversies   

All the events above are facts, and as I said, i think we might put the two sides of the story for each.

I also started editing the existing page. Im aking out highly subjeective comments, like he "surpassed his peers at an early age", he insprired generations, he is admired by leading politicians etc. I also added that he is viewed differently by supporters and detractors. Some objective editor should check and verify that these removals are intended to make the article impartial and are not vandalisms.