The Texas Hiker false equivalency wagon teeters on.
That being said, if the courts and IRS and state laws iron out the hereditary rights issues, visitation, inheritance, and all the other headaches that are and would be entirely unique to the issues of plural marriages (remember: marriage is expressly recognized by government--not by religion--hence the stink-up TH has always had about legality of marriage), and can effectively determine a means through which all parties individually agree that a life of sperm-swapping and baby-incubating is in their mutual interest, and arrived at through sound mind and legal age of consent, then I can't see a problem with this.
Yup. I don't care what consenting adults do as long as they aren't harming others.
So as long as the various sticking points about rights are worked out, I would support polygamy.