Moving to another state in America is something poor people do all the time. Regardless, does a modest cost in a small minority justify putting 9 elites in DC in charge of the moral law of the whole country?

The right of people to govern themselves is important even if we disagree with how they do it. Note the EU Human Rights Court came to the exact opposite conclusion a year after Obergefell, finding no right to marriage for same sexual couples under the EU convention on human rights.

If you look at constitutional law in western Europe, no country has a court that intrudes as much into social issues as the US Supreme Court.

Far greater than the options of someone who is gay and would have to move to a different country instead of just a different state. For example, the existence of sanctuary cities for undocumented immigrants is entirely dependent on a lack of federal power to override the will of the states.