The first openly gay bishop in the US Episcopal Church split opinion at the Christian festival as much as he did within the worldwide Anglican Communion, which has been fiercely divided by Bishop Robinson's ordination in 2003.
Bishop Robinson was greeted with a standing ovation by the hundreds that had come to hear him speak about his sexuality at the festival.
However, his presence as a main speaker at the festival has been widely criticised by various Christian groups, with some boycotting the festival this year in protest.
Bishop Robinson told listeners: "I came out because God called me out. We do God a disservice by denying who we are.
"The question the church is trying to answer at the moment is if we have been wrong in our views towards gender, race and the disabled, could we also have been wrong in our stance towards homosexuality? And if so, do we have the courage to admit it?"
Pro-gay supporters were not the only ones that came to listen to the Bishop of New Hampshire. Phil Ascroft, 25, a teacher from Preston, told This is Gloucestershire: "If you don't listen to all the arguments then you can't make an informed decision one way or the other.
"One of the attractions of the Greenbelt Festival is that people are encouraged to listen and be open-minded."
However, others attending the festival chose to avoid Bishop Robinson's addresses. Scott Provan, 27, from Cheltenham, told This is Gloucestershire: "I will not be going to hear Gene Robinson's talks. It's not for me.
"I don't believe his lifestyle promotes good Christian values. Although God accepts people from all walks of life, I think by being a practising homosexual he is going against biblical principles."