Well since we don't have any images of pro-slavery protestors, your whole argument is now invalid. :-P But more seriously, even those using it for justification of slavery had to twist or interpret the words in a way that those opposed to gay marriage do not. The Bible is rather direct and clear on its stance about homosexuality, in a way that I don't think it is in regards to slavery. In other news, I almost totally missed this post due to the way notifications about the same topic stack. Good thing I came back on a whim.

I think that 5 lines on how to conduct the sale of your daughter is a pretty overt way of saying "you're allowed to sell your daughter into slavery, also slavery is chill".