<rant>
Rainfire's interpretation of the intent of this joke is unenlightened and just plain ol' run-of-the-mill wrong. I felt I should respond to it in some fashion.
This joke (in this incarnation anyways) was in response to Dr. Laura publicly denouncing homosexuality as a sin, using the Old Testament to back up her stance. This is, of course, a ridiculous thing to do. The author of the "letter" above was showing up the pure stupidity of Dr. Laura's suggestion by demonstrating that many of the laws outlined in the Old Testament have simply no bearing on modern life. They are several thousand years old, it's no surprise.
And from a theological point of view, if you are a Christian, the Old Testament cannot be used as a reasonable method for determining God's view of an issue (such as homosexuality, premarital sex, whatever) since the whole point of Christianity is that the death and resurrection of Jesus Christ forged the New Covenant, a completely different and radical (in their terms) agreement between God and his people. The New Covenant is about pacifism and forgiveness of sins. God as we know him from the Old Testament was a being of fire and fury. Would the Christian God turn the river Nile to blood? Hell no (no pun intended).
If you're going to use the Old Testament, you have to take it for what it is - the Jewish Scriptures, a document which, to a certain extent, represents the culture and religion of ages past. If you are going to make claims from a Christian perspective, backing them up in this way is a seriously bad move. Certainly there is value to be had from the Old Testament, but not by attempting to literally apply laws which make no sense in a modern context.
</rant>