Why? Check it out.
The vote in Iran's Parliament was 148-5 in favor of the measure, showing the "broad, popular support" for it.
Note that the death penalty is authorized for so-called "corrupters of the world". Wow, how could you corrupt this world any more than it already is? But that's a Christian concept (that "the world" is corrupt), and in Iran, Christian concepts are treated somewhat like porn.
Oh, wait. The Left is getting confused again.