I cringed at first, but overall, it was good for a Beck piece. He does completely miss the point that people making political decisions may not match their preferences. For example, Obama is not as vilified as Miss California because people expect he may be hiding his real preferences behind his politics.
I have had several discussions with people who were against gay marriage. One guy brought up the slippery slope of polygamy and then people marrying animals and then pedophilia. One guy there said, "Wait a minute, there is a great difference in consenting adults and the rest." But then he added, "But you are right about polygamy. I guess I support that as well then." What is interesting is that I have heard 3 people who went through similar conversations come out with the same conclusions. (Of cource, I hand out with scientists.)
So I am hopeful that after gay marriage is common, that people will see that polygamy is the next logical step. Society will have to adjust. For example, insurance provided by an employer will need to be adjusted to deal with large marriages.