Idiot shoots 14 people at Batman movie in CO.

[Earendil]

I can hardly believe I"m going to engage here, but what the heck...

Because, he will gain the additional benefits that our justice system will afford him

Maybe, but it wouldn't surprise if, in an attempt to make all inmates treated equally, that they aren't all allowed some small "benefit". At work I get a religious holiday, it may have started because some group demanded a day off, but the end result is that everyone can use it for whatever they want.

in an attempt to prevent further offense to those members of that faith worldwide.

That would not be why. The federal government doesn't want to get into the realm of identifying who is and is not a real believer of a particular faith, however no main stream follower of Islam is going to be up in arms if this guy isn't treated well. They are more likely to disown him in fact, as his fellow inmates have.

He also gains additional notoriety and press.

Outside of a sadistic "look at me!" exactly what does this buy him? You think he'll get chosen for the front cover of a Wheaties box? He's going to jail for life, not 5 years.

He can claim special rights and privileges that members of other faiths do not while in custody. Do you think regular inmates get advised on map points of compass directions? He has gained the right to know where to pray towards Mecca

"regular inmates" can probably ask a guard "Yo, which way is north?", or, you know, look at the sun and figure it out themselves.

and may, or may not gain additional items other inmates may not, including prayer rugs. He is smart because he is taking advantage of the system

Maybe he is, maybe he isn't. The only things you've named are the cardinal directions and a small rug, neither of which strike me as being worth "pretending" to pray for 5 hours a day.

and gaining sympathy.

I don't think so, and here is why. When people are locked away and reflect on their life, they often times find faith. That faith may change who they are, how they think, and how they approach life. This in turn might cause others to treat them better as they are a "changed person", and probably show remorse for their actions.

This guy is not doing that. He is claiming a faith and saying the faith justifies his actions. The problem is that the religion he chose does not promote this kind of violence, and he has shown no remorse. He is gaining no sympathy for those that aren't Islamic, and he certainly isn't gaining any from those that are (I'm excluding the cave dwelling fanatical type). He is proving himself to be a bigger nut job, which grants him an ounce of pity perhaps, but not sympathy.