Unsolicited religion irritates me

A couple of Jehova's Witnesses knocked on my door this morning, and I'd already opened it when I realised what they were there for. They wanted me to take a Watchtower and read it, and said something along the lines of racism being endemic in society today, and so I should join their faith. Apparently they felt that their religion wasn't racism. I told them that I didn't think Cthe bible was against racism considering it condones slavery, as long as the slaves come from neighbouring countries, which is fairly racist for several reasons (aren't those from other countries good enough to be our slaves?). Anyway, one of them tried to tell me that while it did say that in the bible, it was using a different definition of slavery. Umm.. yeah, right. Then when I said that it was the same definition of slavery that we use today, he said that it also said that the slaves had to be treated well and they could only be taken as slaves if the slave had entered the profession of slavery voluntarily. Now, while it's true that one, back then, was allowed to choose to become a slave, it wasn't the only means by which one could enter the trade. Taking people from neighbouring countries as slaves was allowed as one of the spoils of war, and that doesn't sound voluntary, in my opinion.
I also told them that I preferred science and fact, as opposed to fairy tales. Our conversation didn't last much past that point.
One thing that amused me in all of this was that the first one to speak didn't seem to know much about the bible at all, and didn't know that slavery was even mentioned in it, let alone condoned. So, that led me to believe that I, as an atheist*, know more about her bible than she does.


* atheist = person capable of thinking for him/herself. (just a short vocab lesson for you)