"I've never really got anything from your personality. Tell me something fun you've done in your life. I'm trying to make you fun but I'm failing."
Cowell then added: "I just don't think people are going to like you very much."
He then told Stephanie McCourt, also 27: "People don't like you at the moment and I think it's just the way that you are is not very friendly, not very warm."
Another contestant, Vicki Ann Nash, was in tears after being eliminated from the show, then saved - then eliminated again.
Blackburn shunned the show's "negative" tone on Twitter adding that he felt it was a bad environment for the young contestants.
Blackburn retweeted a number of messages sent to him supporting his stance.
An X Factor spokesman came out in support of the segment saying it had been part of the show since 2013.
"All contestants are therefore aware prior to application that this is a key part of the audition process and are fully briefed on the format before they go on stage.
"Support is provided to contestants throughout the competition and a psychologist is always available and in attendance at all of the auditions."
Sunday's episode was watched by 7.4million. In previous years it could command around 10million for anticipated episodes.
- Daily Mail