There are a lot of decent human beings on this earth, and some of them happen to be Christian. A couple of them are my friends, and they know well enough to support equal rights because they have read Leviticus. ALL of it. And they know that if we were to use three lines out of it and ignore the rest, that would be called "taking it out of context," which is considered a fallacy.
The book of Leviticus is used by frightened, old white men to suppress people who are not old, white men. It was used to justify slavery, and it is used to justify excluding a whole ton of people equal rights. Yes, I am about to quote scripture. No, I don't need your opinion. I realize that people diaper-rash sensitive when an atheist quotes the Bible, but I am not out to disprove anyone's religion, merely to clarify the relevance of the book of Leviticus in modern times. I just want you to pay careful attention. I will give both the NIV and King James versions of these verses.
This is Leviticus 25:44.
NIV: Your male and female slaves are to come from the nations around you; from them you may buy slaves.
KJV: Both thy bondmen, and thy bondmaids, which thou shalt have, shall be of the heathen that are round about you; of them shall ye buy bondmen and bondmaids.
The Bible is almost never read or studied cover to cover, much like the Patriot Act, and most people know just as much about both.
Let me give you the most used verse in the fight against gay rights. Leviticus 18:22. Burned into my brain at this point.
NIV: Do not have sexual relations with a man as one does with a woman; that is detestable.
KJV: Thou shalt not lie with mankind, as with womankind: it is abomination.
You really ought to read this particular book. It is full of strange instructions for a rigid, strange lifestyle that cannot be considered normal in modern society. Leviticus 15:1-33, for example, pertains to the apparently unclean status of a woman during menstruation, for example, It's really just very bizarre and uncomfortable to read in 2013. I would consider most of it offensive, personally. The whole book of Leviticus is offensive in a modern context.
If we are to use this ridiculous and no longer relevant set of rules set forth for a nomadic desert tribe as rules for modern living, it would make sense that we would have to ignore all those silly rules for women, because that's just not cool anymore. And slaves are so 1800s. Let's ignore those rules, too. But you know who it's still okay to single out? Oh, most other people. Until they win their rights. Eventually, those verses will be ignored, too. Eventually, the whole book of Leviticus can be disregarded, thankfully, because it is not compatible with modern life. Period.
HOWEVER, it should be noted that there are a lot of stupid, trite, idiotic people arguing for my side as well, some of them on my news feed. I have to address this, because it is a glaring issue. Fellow atheists, pay careful attention.
Proving the existence of a unicorn is not the same as proving that God exists. You cannot do both arguments and call them parallel. God, in theory, is an all-knowing, all-powerful entity and creator of the universe as we know it. A unicorn is, in theory, a magical horse with a horn. They are not the same. If you must use an example, use something like the flying spaghetti monster, because it at least represents the same set of requirements for proving its existence. You have to understand the religion in order to argue against it, and if you simply cannot be bothered to understand Christianity, you ought to avoid the topic until you know how to do some research on philosophical arguments. That's what an upstanding, responsible person would do, rather than become a vehicle for uniformed hate. I grew up in a Christian household, and I consider the majority of my fellow atheists ignorant of most world religions.
Personally, I see no need to disprove anything. I merely see the need to point out why certain arguments are completely invalid. You are welcome. It's not my intention to offend anyone, but I'm sure that I have done so.