"Why is that wrong? Because you, and the vast majority of people think it is. I agree. Which means that those laws are legislated morality of the majority."
No, it's wrong because murder results in the death of another person, theft results in property loss and potential injury to another person, rape results in potential death, injury, unwanted pregnancy, diseases, and trauma to another person, and arson results in property loss and potential injury/death. All involve non-consenting parties. If I were to force you to marry another person of the same sex under some sort of threat, that would be illegal. If you simply chose to marry someone of the same sex, how does that harm anyone else? It harms me no more than it would if you married someone of another orientation, presumably a straight person.
Whoever I marry, if I marry at all, will be fully aware that I'm pansexual, just as most people who bring the subject up around me are, and none of them are harmed by that knowledge. Were I to marry or date another man (probably not gonna happen), the only person that would be potentially harmed would be myself and my partner because of the hatred that flows throughout every inch of this earth. You would be perfectly fine, and your traditions would be perfectly fine. Your property would be fine, you wouldn't experience trauma, and you could explain to your children that love is love and no dumbass politician or bigoted something-or-other is going to get in the way of one of the strongest facets of your humanity.