Labrat,
I'm not quite sure what connects the first three restrictions on marriage, either. The only connection seems to be that society has decided these types of unions would be bad ideas, each for a different reason.
As far as the validity or honesty of arguments which claim the existence of sound reasons why society might consider same-sex marriage a bad idea, may I suggest you seem to be engaging in a logical fallacy known as the "straw man". By presenting my (supposed) arguments for me, and then knocking them down, you do me an injustice.
I know that your position is based on what you truly believe to be a tolerant, charitable, and loving attitude towards all members of society. I also know that proponents of same-sex marriage do not, as a rule, assume the same about their opponents. Rather, we are assumed to be intolerant, uncharitable, and, yes, even hateful. Thus, our arguments are dismissed as "biased" before they have even been presented. How sad.
