So in the homosexuality is a sin
node, the people arguing for homosexuality's sinfullness bring up Leviticus
--the book of the "Old Testament
" or Hebrew Bible
that contains many of the detailed strictures and laws that make life complicated for Orthodox Jew
And well-intentioned Christian liberals pipe up with a traditional Christian response, which I'll paraphrase.
"Well, those are the nasty and vengeful laws of the Old Testament. We Christians are inspired by the the loving message of Jesus Christ in the New Testament."
How bigoted! How condescending! There are tens of millions of people who follow the teachings of the Hebrew Bible but reject the revelation of Jesus. As Andar pointed out, Jews aren't any more likely than Christians to believe in an angry, vengeful God. Jesus' viewe of a loving God was an expression of an existing Jewish belief, not a radical contradiction to it--which is why Jesus himself said that there was no conflict between his vision of God and the strict Levitical laws.
To pretend that Christ and Christians are responsible for the image of a gentle, loving God is anti-Semitic, because it presents Jewish religion as being more violent and primitive then the enlightened Christian one. It's important for Jews and Christians to talk about their differences, but it is absolutely wrong for Christians to caricature Jewish beliefs and present them falsely.
Most of the people who talk like this are also very concerned about being sensitive to Judaism, and so it's particularly sad that they use allow anti-Semitism to creep into their arguments. Be careful, and think about the implications of what you're saying.