So much I don't understand

In all the euphoria over the election of Barack Obama to the Presidency of the United States, some other stories were briefly overshadowed.

Several states passed one version or another of attempts to deny certain rights to people based on their sexual orientation.

I understand that many people believe that Homosexuality is a sin.

What I don't understand is why that religious based belief should be the law of the land. What is the justification for discrimination against people because of who they love??

I just don't understand.