The army was the Byzantine Army and the Emperor did not give them a choice.
What is said is that they liked keeping their HEADS!
>> The army was the Byzantine Army and the Emperor did not give them a choice. <<
The Byzantine Emperor certainly did implore his bishops to attend. However, the Byzantine Emperor was already 95% destroyed, consisting only of the small Isthmus that Constantinople was on, and the southern Greek peninsula that Athens was on. Very few of the Eastern bishops were from territory under his control. Any persuasion he had on them was that they shared his desire not to see Constantinople fall to the Turks. The notion that he used his army to force them is downright comical.