Pop superstar judge Perry, 33, faced a backlash after she unexpectedly gave 19-year-old performer Benjamin Glaze his first kiss ahead of his audition.
Glaze said it made him feel “uncomfortable” and that he wanted to save the moment for his first relationship.
Richie, who judges the US show based on Pop Idol with Perry and Luke Bryan, said he felt like their “babysitter” because they have “no filter”, but said he believed she did no wrong.
“Katy is one of those phenomenons, she can do things and get away with it. It’s all in fun, it’s all in jest,” he told the Press Association in Los Angeles.
“I was there, I’m a witness to it. She was hamming it up, then it was nothing more than that. Of course when you do it to the public you’re going to get two different views of what’s happening, but trust me it was all in fun.
“Everybody’s having a good time – including the contestant.”
Glaze, from Oklahoma, told The New York Times after the scene was broadcast last week that it made him feel “a tad bit uncomfortable” and that he would have denied the kiss on the lips if she had asked.
“I wanted to save it for my first relationship,” he added. “I wanted it to be special.”
He wrote on Instagram that he did not believe he had been “sexually harassed” and thanked Perry for “launching my career into the sky like a flaming cannonball”.
On the show, Bryan asked if Glaze had “kissed a girl and liked it” in a reference to Perry’s hit I Kissed A Girl.
Glaze explained he had never been in a relationship and would not kiss anyone outside of one. Perry summoned him over and let him kiss her on the cheek.
But she was disappointed with his effort and requested another. She quickly turned her head and caught him on the lips – to his shock.
He was rejected by the judges after performing Nick Jonas’s Levels.
Richie, 68, was speaking in anticipation of his June tour in the UK, during which he will visit areas including London, Hove, Perth, Shrewsbury and Carlisle.
Tickets for the tour, during which he plans to play some of his biggest hits, are on sale now.