It's Always Sunny

so rape or murder is no worse a sin than say eating pig, which is also forbidden by the bible?

Eating pig is stated as forbidden in the Old Testament (first half), not the new (second half). Therefore, yes, rape and murder are terrible terrible things but no, pork consumption is not. Christans don't follow the Old Testament anymore because there are new "laws", so to speak.

Ok. That's fair. But is guest correct in saying that no sin is greater than another in your belief system? That rape and murder are no greater sins than say, adultery?

It's a simple way of saying "no matter what you do, or how bad you think it is, you're still going to suffer the same" God is a dick.