"He has profiled himself as an Utøya survivor, so to have something that sounds similar to a machine gun in the chorus is extremely cynical and vulgar," Pedersen, a veteran Eurovision commentator, wrote in his review of the country's contenders. "Shame on you Mo! Shame on you NRK!"
On Sunday night, Abdi Farah was beaten by his Sony label-mate Carl Espen, in the Norwegian final of the Melodi Grand Prix with the piano-driven, slightly folky torch-song Silent Storm.
Pedersen's review of Abdi Farah's entry must have stung almost more than losing, however.
"This is a botch-job of a song that has stolen more than is good for it from Russia's 2008 winner," he wrote in the Helgeland Arbeiderblad newspaper. "Mo sings in an overblown and pretentious way without regard for text or melody."
The 21-year-old and his managers at Sony Music have tried hard not to overemphasize his experiences on Utøya, with Abdi Farah in interviews maintaining that the song, Heal, is not directly about his own recovery from trauma, and also normally refusing to answer questions about what happened to him on the island.
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Pedersen's savage review drew an angry reaction from the 23-year-old singer's supporters.
"Jostein Pedersen writes that Mo has "profiled himself as an Utøya survivor," the comedian Klaus Sonstad wrote on Twitter. "That's not so much a blow below the belt, it's more like a knife to the heart."