I'm a christian myself. And bible has teached me that everyone is a sinner, no matter if religious or not. Religious people just tend to try to live as sin free as possible, but the way Jessica's grandmother went about the religion thing is absolutely nuts to say at least.
As ironical as it might sound, some people are turned off by religion because of people preaching like that and might choose to be atheists later on because of it.
There's even saying, if you found guilt and shame, you have found religion. If you found peace, you have found Jesus Christ.
Nothing wrong for believing in god or Jesus. But please, respect everyone. Even those that disagree with you.