Why did a blog say that Muslims claimed responsibility for the Oslo shootings and then retract the claim?

"Many mainstream media outlets ran this claim." And they don't even bother to disclose where they found this information. Most reasonable people would know that Zionists do not like Islam and Zionists have long been demonizing them and portraying them as terrorists. I wouldn't be surprised if Israel had something to do with the incident in Oslo because they have long been involved in many false-flag operations against Muslims and Arabs as a whole. And these same people have control over the media.