The Big Benghazi "Why" ?

As more information about who knew what and when in the Benghazi case, we have learned that top White House officials knew within hours through the recently released email.
White House notified
We also know that top officials watched the attack place in real time via drones and direct phone connections.

But what we don't yet know is - 
WHY ????
Why did the attack take place?
Why didn't they send a rescue team?
Why were they meeting in a clandestine place?

Why was the CIA involved?

Why was the Turkish Ambassador there minutes before the attack?

Why are there still so many unanswered questions before the election?

And last …

Why are they willing to lie to cover this up?

Glenn Beck has a theory about gun (arms) running taking place in Benghazi with some very shady participants.  You can see what he says here:
Beck explains gun running
The video is at the bottom of the post.
He calls it "Fast & Furious times 1000"