I don't know -- I am not against interracial marriage. My point isn't whether or not someone has a valid reason, but the fact that they can have an opinion.
A lot of the time, people just feel a certain way about things for reasons only known to them.
At any rate, the comparisons are not worth replying or, for a specific reason:
You're saying my argument X (disagreement with gay marriage) is false because argument Y (disagreement with interracial marriage) was false. This is a fallacy of virtue....which is why I am wholly ignoring them.
If you want to show me why I am wrong about disagreeing with gay marriage, tell me why I am wrong about gay marriage...don't tell me why racists were wrong 99 years ago, or why slave owners were wrong.
That's like saying I was wrong for eating a cheeseburger because by great-grandfather was wrong about eating a can of soup.
You were born in a time when the fear and hatred of one thing has become accepted(with no negative consequence) and simply focused on another one. Same human weakness. Still pathetic.
You are wrong on gay marriage simply because you want to deny rights to a group for no actual reason aside from your fear and hate towards them. Giving them equal rights does literally zero to harm you.
People continue to practice hate and fear throughout history. It is simply funny that you can't see that you are the exact same kind of person as them, but you have a new focus.