Why is the Obama administration lying about Benghazi and trying to cover it up?

Because they didn't want to admit that they were wrong. They didn't want to admit that they set up Stevens by knowingly reducing security during 9/11. Then they brought up a little seen trailer that the Muslims took up after the protests on 9/11.

Sorry, but when they chant Obama, we are Osama in the streets that has nothing to do with any movie and more about how we took out Osama Bin Laden.

Then again, anyone in politics tell at best half truths when their mouths move.

they didn't lie, they simply passed on the information they had at the time. there is no cover up either, everything you need to know is on the public record, much to chairman Issa chagrin.

If he is then its probably strategic, top secret and therefore "need to know," and therefore you probably don't, so quit whining about it.