It seems to me that courts are striking down bans on gay marriage, and thus, now various states have gay marriage.
It also seems to me that if these bans had not existed, gay marriage advocates would have had a much more troublesome time. They would have to go to state legislatures and get marriage redefined. The bans provide the redefinition and change the venue to federal court.
I believe this is actually about lawyers. Heterosexual marriage has already been raped and pillaged by the divorce industry, gay relationships are simply a fresh supply of funding the lawyers can't wait to get their hands on. Both parties are full of lawyers, and lawyers know how to game the system. They can be quite brazen because most folks who aren't lawyers aren't going to realize what's going on.