Why are the Brothers Tsarnaev described as 'self-radicalized' but Loughner, Lanza, Holmes associated with the 'Right'?

As soon as the images and identities of the Boston Bombers were revealed to the public, media reports began describing the Brothers Tsarnaev as ‘self-radicalized.’ Here is the Washington Post, The New York Times (describing President Obama), CNN, CBS,  and the Boston Globe all using the term with little question.

On the other hand, Jared Loughner, who shot Gabrielle Giffords in Tucson, was connected to the Tea Party by Debbie Wasserman-Schultz.  ABC News’ Brian Ross claimed that James Holmes, the Aurora Batman movie shooter, might be a member of the Tea Party.  It was pointed out that Adam Lanza, the Sandy Hook murderer, had an NRA certificate.  These were all constued as relevent connections and associations. 

The obvious reason for this discrepancy is that the media leans undeniably to left and the leftist world view includes the principle that murdering people with firearms is a characteristic of the right. This principle is preferred to the more reasonable idea that mass-murders are mentally ill or insane.  So perhaps in the eyes of the media, this connection “makes perfect sense.”

But the story is quite different for the Brothers Tsarnaev.  Somehow, these fellows are impervious to any influence of their immediate, regular and obvious surroundings.  Sui generis, they blew up a bunch of people at the Boston Marathon. The questionable associations of the Tsarnaevs are certainly more solid than those connecting the mass murders to imagined right-wing associations.

The Brothers attended a mosque in Boston that has produced multiple noteworthy Islamic terrorists.  The older brother Tsarnaev beat his former girlfriend for not complying with shariah-based dress codes for women. The beataing was the reason he was arrested for assaulting his ex-girlfriend, an arrest that did NOT lead to his deportation.  Tamerlan had a YouTube account with videos on radical Islam and terrorism.  Despite multiple warnings from Russia and Saudi Arabia about the Tsarnaevs relationshtip to radical Islam, they went undetected and unexamined here in America. It seems that the media is not the only ones with a leftist, politically correct world view, but US intelligence agencies as well.