Well, for one thing, even though SCOTUS allowed gay marriage in all 50 states in 2015, many states still have anti-gay marriage laws on the books. Efforts to repeal the outdated laws remains difficult to this day. Nevada voters will be voting to repeal theirs in November. Other red states have legislations that have actually voted to keep their laws on the books. They're probably hoping the new SCOTUS (after Trump installs Judge Ofdon) will ban gay marriage again.
https://www.nbcnews.com/feature/nbc-out/states-across-u-s-still-cling-outdated-gay-marriage-bans-n1137936