You're contradicting yourself. If the Supreme Court can declare state marriage laws unconstitutional when they are racially discriminatory, then they can do more than render a "non-binding" opinion-- they can issue a binding order. That's exactly what they did in Loving v. Virginia in 1967-- they didn't render a "non-binding opinion" that anti-miscegenation laws were unconstitutional; they ordered states to allow racially-mixed couples to marry. (Some Southern states didn't formally repeal their anti-miscegenation laws until well into the 21st Century, but that didn't mean that blacks and whites couldn't marry in those states, or that no one could get married in those states.)
Your point about gays being different from Hispanics has nothing to do with the Supreme Court's jurisdiction to interpret the 14th Amendment; you're just disagreeing with their interpretation. (As it happens, so do I, but that doesn't mean the Supreme Court had no jurisdiction.)
The nature of humans requires opposite genders for humanity to survive. That some couples may not produce offspring does not invalidate the requirement for opposite genders. Homosexual unions can not - by their very nature - produce offspring.
Interracial marriages produce offspring, homosexual unions can not. Laws banning interracial marriage did not touch the definition of marriage. The USSC has arrogated to itself the authority to alter the definition of marriage.
Comparing homosexual unions to bans on interracial marriage is nonsense.