It's always a good thing when someone sees the light.

I don't think these people know what "hypocrisy" is. It would be hypocritical if someone supported same-sex marriage, but if their OWN child were to be homosexual and wanted to marry someone, they would suddenly be against it.
It would also be hypocritical if they were to support their child in their life, but still publicly opinionated their opposition to same-sex marriage.
Changing one's point of view does not make one a hypocrite. Regardless of the reasons that made you change your position, that just shows that you have a sufficiently ductile brain that you can actually change your point of view when given sufficient cause to do so.
Hypocrisy is when you have some view for some cases, and another view some other cases. Ie. when you're not consistent in your thinking, speech, and actions. In other words, hypocrisy is when you "talk the talk, but you don't walk the walk".
I shall now generously share my correct views on this matter, so that everyone can agree with me
The solution to all problems related to "gay marriage" is obvious... all you need to do is separate the concept of marriage as a religious union, from what it objectively is - a secular union between two people.
I don't really give a **** what different religions think about their particular view of marriage. It shouldn't even matter. All arguments AGAINST gay marriage simply fall apart when you consider what marriage actually IS from secular point of view - a registered relationship which grants you certain benefits and gives you certain responsibilities.
Anyone should be allowed to register such a relationship with another consenting person (when both are legally adults, obviously). It is not the state's business to arbitrarily name conditions on who you can or cannot register such a relationship with. Saying that same-sex couples should not have this right is discrimination, whatever words are used for it.
Churches should have absolutely no business in the official registration of such relationships. Especially in the US of A where it is actually specifically mentioned in their constitution that the church and the state are supposed to be separate entities, yet the clergy still somehow holds power to officiate marriages.
Churches, then, must make up their own mind about whether their god approves of same-sex couples or not, and based on that decide whether they will allow same-sex couples to go through their particular religious marriage rituals in their church, or not. This is an issue about religious freedom, and as ridiculous as I think it is, churches should have the right to decline to marry same-sex couples. But that matter is between the church and its members. If you disagree with your church's official position on whether same-sex couples can be married or not, you're always free to find another church that will perform the marriage.
After all, why belong to a church that you disagree with?
However the churches' right to refuse same-sex couples has absolutely nothing to do with whether same-sex couples should have the right to register their relationship via official channels and get the same benefits and responsibilities as heterosexual couples. And the official marriage registration should have nothing to do with the clergy, but instead it should be done in the magistrates.
The issue of polygamy should similarly be treated separately as a religious issue (which doesn't matter) and a secular issue (which is what actually matters). I don't have a particularly strong position either for or against. I think from secular point of view the biggest question is, if there is a group of people living in a polygamous relationship, should all participants receive equal tax breaks, or should it be considered as a singular marriage where the tax breaks per person depend on exactly how many people are in the relationship.
Religiously, I hold no views on any matter.Ethically and morally, I really don't see anything wrong in any relationships
between consenting adults*, so polygamy itself cannot be a bad or a good thing - it is what the people practicing it make it to be.
Notoriously however, polygamy is often practiced in patriarchal societies or even cults where the conditions for freely given consent are usually not fulfilled. In such cases I consider the "consent" usually given under duress - either by threat of being thrown out of the cult, or threat of punishment of some other kind (physical or otherwise). These schemes often concentrate on keeping their members - especially females - dependent on the males, economically and emotionally, which means leaving the cult is not usually a viable option and thus the decision to enter polygamous relationship is not consent in my view - it's a decision made under duress, with no other options. Needless to say, I find polygamy in these conditions to be despicable - especially in those cults where underage girls are sent to polygamous relationships by parental consent.