He also explained that making the decision to axe Pearson was difficult.
"I was hurt. I felt like I was powerless in the situation — like I was just punched in the gut. I was forced to let down a friend, someone that I really wanted to just love and support, the way Jesus tells us to. I was being denied that opportunity, at my own festival. It was a horrible situation," he said.
Despite Diello's decision, Pearson praised him in comments to Billboard.
"The owners are awesome and their hearts are awesome and that's why they were inviting me in the first place. There was no way they would have been able to have the festival. If they keep me, I'm not going to perform anyway, because the festival is not even going to happen, and the festival owners are going to lose probably hundreds of thousands of dollars," he said.
Pearson, who is still friends with members of Switchfoot and Relient K, two of the Joshua Fest headliners, said he decided to attend Joshua Fest anyway as a spectator but was surprised when a member of Five Iron Frenzy, a ska-punk band whose drummer Andrew Verdecchio is atheist, asked if he would perform with them.
"They were like, 'Hey, what would you think about coming up and singing our last song with us' — 'Every New Day,' which is one of their biggest songs," Pearson said. "They were a band that I went to tons of their concerts in high school and looked up to, and so to have them ask me to do that was amazing. They checked with the owners first, and we all decided — it's not me doing my own set, but it's still a way that I can go up there and be a part of the festival.
"So it turned out to be a really beautiful thing. I think there were a couple of surprised looks that I was there by a couple of people who didn't want me there, but everybody was friendly. Of course I wish I could have done my own set, but in some ways this almost felt more powerful, because it was this band that I looked up to growing up that a lot of the fans looked up to, and all these guys from the other bands, too, standing with me in love."
Verdecchio said having Pearson perform with Five Iron Frenzy was about making a statement.
"Having Trey come up on 'Every New Day,' which is sort of our worship anthem at the end of every set, I think made a pretty big statement. Like, he believes in the same God you do, but you're going to excommunicate him because of his sexuality?" he asked.
Reese Roper, Five Iron Frenzy's singer said the band was planning to boycott the festival to make a statement but opted for making a statement by allowing Pearson to perform with them instead.
"We had all talked as a band about just dropping off of [the festival], just to make a statement, like if you're not gonna let him play, then we're not gonna play. We don't like to deal with that kind of intolerance. Especially to me, if you're espousing being full of the love of Christ, that's just not how you do it," Roper said.
"Personally," Roper added, "I feel like the Bible is not clear enough on it (homosexuality) to say. But I do know that it is clear that we are to love each other as Christ loved us, and I don't think the Church is doing that."