polygamy and gay marriage

Okay...my husband's friends are a little odd. This is the argument I got tonight at dinner. "Well, if gay marriage is legal, then polygamy should be legal, because....i mean....what's the difference?" This husband and wife duo teamed up on me and badgered me for 20 MINUTES on how polygamy was no different then gay marriage. Now mind you polygamy may work for them because they have a one sided "open" marriage and don't want to get divorce and can stand fighting constantly, but for most people who didn't grow up in UTAH in the 1800s, polygamy is a new fangled thought brought back to current attention by the HBO product placement show Big Love. After explaining to me how gay marriage and polygamy run hand in hand, I got a 30 second rebuttal that included the fact that gay couples have a lower split rate than heterosexual couples and though I haven't made up my mind completely on the issue that I felt that it was completely different than a man with 3 wives. I lead off with the tax implications that have 3 wives would have. Say one man has 3 wives and each wife has 3 kids, if we restructured the tax code to legally allow this to happen, that one man would have 9 standard deductions on his tax return, not to mention his earned income credits, his child care tax credits, and educational deduction. Then the wife of the duo came back to me and said that he would only legally be married to the first wife and the other 2 wives would claim their own children. To which i responded, "so pretty much he has one wife and two hoes and 4 illegitimate children...how is that any different from the problems that are plaguing communities now? the only difference that it really makes is that his hiram lives with him and his legal wife consents." To which, she responded, and I quote, "what difference does it make...you can only claim 3 of your children on your tax returns anyway." I quit listening at that point because sure I'll journey with you for a minute down the road of aruging, but when you start whipping out false evidence about tax and try to convince ME, a self-proclaimed "reasonably good at taxes" law student about how the modern tax code works, you've lost. And I hate to make a bitch cry. So I backed off, but they kept talking. So I finally did something they both understood. I took my fingers and did the "i'd rather blow my brains out then listen to you turn your wheels" motion and turned around and walked off. The only thing worse than having a debate with someone who may be right is having a debate with someone that has absolutely NO idea what they are talking about and them not stopping.