Marriage Hypocrisy

This November, voters in my state will be asked to answer yes or no to the following question:

Shall the Minnesota Constitution be amended to provide that only a union of one man and one woman shall be valid or recognized as a marriage in Minnesota?

So, during the last few months, we have been bombarded with ads like this:


I cannot help but wonder why this supposedly fair and open-minded individual wants to limit marriage to only "two people." What kind of bigoted, hateful person would tell polygamists that they have no right to marry whomever they please?