What exactly are you saying here, that they should stop moderating the iAmA subreddit altogether? Reddit has shown they will actively remove and replace moderators who do not kowtow to their demands.

What is this adapted from if I may ask?

How does that make any sense? A celebrity AMA is like a form of advertisement. I sincerely doubt money ever changed hands between anyone, especially with volunteer moderators at the helm. The celebrity gets to schmooze about their latest project, and Reddit got extra clicks.