The comedian famously caused Ordinary Boys singer Preston to walk off the show by reading excerpts from his then-wife Chantelle Houghton's autobiography.
Asked if he thought he was cruel to the stars, Amstell told DS: "I always felt like it was playing and being silly. The bits which are remembered are the bits when you didn't quite get away with it, so you didn't quite do your job properly.
"I don't think I was too mean. More often than not I would regret not saying something than saying something. I always felt that my priority was to the audience. Their laughter was more important than the feelings of the actual people there."
He added: "I think sometimes I treated people as their brand, but that often came from the fact that they had let go of themselves as human beings and created these brands.
"I think once you sell elements of your life to magazines you've then said, 'Please take everything in my life and deconstruct it'. You've sold the most personal moments of your life in a fairly tacky, non-artful way, and you're next to a comedian."
Amstell's debut stand-up DVD Do Nothing is available now.
> Click here to read our full interview with Simon