it doesnt make you an ass, and to be honest i wish i had the guy in front of me right now, i would make sure he felt the same pain that those he killed felt; worst part is, this guy is going to a top security prison where has clean water, food, clothing and probably a nice living space. So he is getting rewarded for killing people to an extent. And to be honest there is really no way to punish the guy; kill him wont solve anything, best you can do is give him in to the mob, basically release him in the middle of the capital with a giant mob of people waiting to pounce on him.
Now the double standard thing is the same as with the nazi war trials, many were sentenced to death, other to live in prison and others got out from 7-35 years later.