There is no Constitutional Right to Exploitation.
A Same sex couple wishing to have a family have to take someone else's child or hire a womb to make one. Definitionally at least one of the parents is not going to be the biological parent. The exploitation potential inherent in that is found in the poorest countries like Nepal where destitute women serve as rent-a-wombs. There are also men who leave their wives for other men and fight for the children with two male incomes versus the income of a housewife who gave up everything to have children. It is not true that there are no victims in homosexual unions always.
"There is a way that seems right to a man but leads to death." (google it.)
Would it be a recruiting tool for jihadi muslim extremists if all of America declared gay marriage a constitutional right? Not a silly question. Would it be such a mobilizing factor indicting the decadent west that it would be of National Security Concern? Apparently we now have to have a gay envoy at the State Department to assuage our allies that Obama is not the reincarnation of the Mayor of Sodom. Think what it does to our enemies.