There is a real reason why laws like this stay on the books. The sodomy laws in particular come in handy in rape and child molestation cases. On CNN today they had an article about some nun that was raped and strangled with her rosary. Since sodomy is illegal there, it gives the cops one more thing to charge this prick with.
http://www.cnn.com/2002/US/09/03/nun....ap/index.html
These laws are sort of "fall back" laws too. There are times when they can't get a rape conviction but a sodomy charge will stick so at least they can get a conviction of some sort.