"I think it's great they're coming around but there's a long way to go," said Peterson, who was raised in The Church of Jesus Christ of Latter-day Saints.
But there were also many groups there to show support for gay-rights issues, including religious groups, corporations and politicians.
It was the second year grassroots group Mormons Building Bridges marched in the parade, making a symbolic show of support from the religious community along with marchers from Unitarian and Episcopalian denominations.
The Rt. Rev. Scott Hayashi, who was bishop of All Saints Episcopal Church in Salt Lake City and Park City's St. Luke's, joined in the first time an Episcopal bishop has taken part in the parade, according to Lee Shaw, a member of the Episcopalian fold.
About 400 people from Mormons Building Bridges faced the 80-degree sunshine to march behind a loud Ska band playing on the Downtown Farmers Market float. For about 90 minutes, the parade meandered up 400 East and took a left onto 200 South for six blocks before ending at West Temple.
Marching under a banner reading Family Reunion, organizer and founder Erika Munson said the group and others have helped change attitudes in the past year: Bishops no longer excommunicate members who come out, and the Boy Scouts now allow openly gay scouts to participate.
The Mormon group drew some of the loudest applause when they passed with signs reading "Love 1 Another," "LDS heart LGBT" and "God loves all his children."
Mike O'Conner ran to get a photo with his iPhone when the group passed. He said as a gay man it helped heal some of his bitterness about the LDS Church backing California's Proposition 8.
"They kinda stick out," he said.
"We're here to support our gay family," Munson said. "It's an inclusive thing. The family is central to God's eternal plan for happiness."
Dressed in Sunday attire, Jason Miller of Cottonwood Heights came with his son, Thomas, 15, and daughter, Emma, 19.
"I think we're at the tipping point [toward greater LGBT acceptance]," Miller said.
Giles Florence of Salt Lake City added, "These are baby steps, but very important ones."
Another smaller contingent of churchgoing, straight Mormons marched under the banner Mormons for Equality, which take a more progressive stance in supporting gay marriage.
"My oldest daughter is gay and this is probably the most important thing I could be doing now," Jennifer Whittle of Salt Lake City said just before tears rolled down her cheek.
Many companies were represented in the parade: AAA, Smith's (which had a line of rainbow-flag-draped shopping carts), Petco, Chase and Wells Fargo (with an old western stagecoach pulled by horses), among others.
The only group to draw slight controversy at the parade was Scouts for Equality, especially when some members said they would wear their uniforms.
Rick Barnes, chief scout executive of the Great Salt Lake Council, wrote about the parade to Scoutmaster Peter Brownstein, who helped organize the march but did not wear a uniform.
"Having uniformed Scouts and Scouters in the gay Pride Parade this weekend is NOT acceptable and NOT allowed," Barnes wrote in an email and capitalized the words for emphasis. "The new policy states that no person, youth or adult, may use Scouting to promote sexual orientation, or any other political or social agenda."
Even so, Neil Whitaker of Salt Lake City wore his Scout uniform, while his son, Kobe McDonald, carried the Utah flag.
"It's about having an inclusive society," Whitaker said.
Organizers and participants said the parade gives gay people an important opportunity to show that they come from all walks of life, that they are no better or worse than other people.
"It's been nothing but a good thing with all the different people here supporting each other," said Angelina Union-Devo, who dressed in a ballroom gown and tiara had just been named Miss Gay Pride and was marching in 6-inch heels.
When not in drag, John Shappee attends business management classes at Eagle Gate College.
"Here in this state people need to feel proud of who they are," said Barbara Cannon, Shappee's mother. "I'm proud of my son. He's taken on a lot of responsibility."
Twitter: @RayUtah LGBT Film Festival
There will be a lesbian, gay, bisexual, transgender (LGBT) film festival July 12-14 at the Rose Wagner Performing Arts Center. More information: Damntheseheels.org.