Your argument has a familiar ring to it.Why same-sex marriage is harmful from a secular perspective
It Imposes Its Acceptance on All Society
By legalizing same-sex “marriage,” the State becomes the official and active promoter of anti-evolutionary sexual behavior. The State calls on public officials to officiate at the new civil ceremony, orders public schools to teach its acceptability to children, and punishes any state employee who expresses disapproval.
In the private sphere, objecting parents will see their children exposed more than ever to this new, alternative lifestyle and children will be socialized and encouraged to act against their primal procreative instincts.
In every situation where marriage affects society, the State will expect heterosexuals and all people of good will to betray their biological inhibitions by condoning, through silence or act, an attack on the natural order and evolution.
Since homosexual behavior threatens the genetic progression and continuity of humanity, society should be very cautious to normalize and institutionalize it as a healthy alternative lifestyle.
Oh yeah - it sounds a lot like this:
Inter-Racial Dating, Inter-Racial Marriage, Judgement Day
By Dr. Ed Fields
Some might ask: Why should the government ever have regulated the behavior of two consenting individuals? Do they not have the right to mate with whomever they choose?
Our forefathers recognized the vast gulf which exists between the White and Black races in terms of equality. They recognized the Negro African race to be an inferior race, child-like, capricious, impulsive and cruel, yet useful for manual labor under the constant direction of the White man.
They also recognized the inherent danger in the presence of a large Negro population in contact with Whites because it invariably leads to interracial sexual relations. They saw the hideous results of low-class White men mating with plantation negro females. They knew that every civilization in history that had used Negro slaves eventually succumbed to the corruption of interracial breeding, leading to the collapse of that society.
Therefore, the founders of America passed laws forbidding White-Black marriage. This was the real motivation behind the segregation laws which existed in the pre civil rights era South. They did not want their civilization to decay and fall due to interbreeding with inferior racial stock!