The Irish pair performed their version of Robbie Williams' Rock DJ
Broadcasting watchdog Ofcom says it is not investigating some 3,000 complaints to ITV about X Factor hopefuls John and Edward Grimes staying in the contest.
ITV, whose message boards was deluged after Sunday's result, said the show "can divide opinion and provoke comment from our viewers".
The Irish pair survived the sing-off with Lucie Jones after judge Simon Cowell turned to the public result.
Cowell has been criticised for not casting his vote for a second week.
Sara Nathan, showbusiness editor of the Daily Mail, told BBC 5 live: "This is why there have been 3,000 complaints to ITV."
But she added the music mogul "was doing the right thing".
"You have to go slightly past a singing competition and realise this is now a big reality juggernaut.
"'Jedward' could be fantastic. They could be really big stars," Ms Nathan said.
Lucie Jones from Cardiff was the least popular act with the public
Maureen Coleman, writing on The Independent's website, asked: "Was this a Machiavellian master-stroke on the part of the most influential man in the entertainment industry?"
An Ofcom spokesman said that it launches formal investigations into complaints including the treatment of TV show contestants and flaws in voting processes, but not the outcome of programmes.
But the watchdog added that it reviews every complaint that it receives.
One complainant to ITV's X Factor message board said of Sunday's result: "He [Cowell] will make more money out of the twins being on the show."
"After banging on, week in week out, about how the twins were rubbish and it was a singing competition, he threw away the chance to prove it," said another.
Cowell has consistently criticised the twins, saying he would leave the country if they won the show.