The fact that many Christians still cling to the fire and brimstone mentality of the Old Testament is a tragedy on par with the Old Testament standing alongside the New Testament and the teachings of Jesus.
As Tinny stated, the old Testament rules do indeed no longer apply. I personally regard the Christians still clinging to them (read: Fundies and Evangelicals...as well as others) as insane. One of the reasons I and many others became disillusioned with organized religion is the rigid adherence (conservatism...bad in things other than politics it seems) to old customs, like the Old Testament.
So basically, the Christians who still persecute others are "wrong" in a sense...whether that matters to them or not is unknown, but it seems they'll keep on trucking with that mentality 'till the end of time. (edit - no cheesy religious pun intended