Some animals are more equal than others. George Zimmerman is a decent American who shot a thug in self defense, so the left hates him. The Tsarnaevs are evil, hateful murderers who intentionally killed an innocent woman and a child while maiming dozens of people who had done nothing to hurt the Tsarnaevs or anyone else. It's no wonder the far left fringe is falling all over themselves to coddle and protect the surviving Tsarnaev while railroading Zimmerman.
Don’t forget how the left is also treating 911 mastermind Khalid Sheik Mohammed, falling over themselves (especially Obama and Holder) to get him tried as a citizen with full constitutional rights rather than tried in a military tribunal. Why? So he has a better chance at freedom. A leftist judge could quite easily dismiss the case due to lack of a speedy trial or torture allegation which is exactly what they want.