Don't blame the POTUS for it, as I have heard in some politically ignorant and obtuse quarters of the vanillacentric GL community today.
North Carolina state Senator James Forrester (R) is the one who sponsored this unjust amendment.. But you won't be able to do much screaming at him because he's dead.
But here's the list of people you can blame.
You can start with all the liberal progressives in North Carolina who sat out the November 2010 midterm election to 'punish the Democrats' and ended up giving the Tea Klux Klan and the Republicans control of the legislature for the first time in 140 years.
Democratic control of the North Carolina legislature was what kept similar Amendment One style constitution bans from seeing the light of day to begin with because they were routinely killed in committee. One they lost control, the Dems had no way to stop them and the GOP introduced, passed it and put it on the ballot.
You can blame the faith based conservafools, Billy Graham, their knee-grow spokessellout Patrick Wooden and other like minded pastors who relentlessly pimped Amendment One and worked like mad spreading disinformation and lies in violation of several commandments in order to get it passed.
You can blame all the registered liberal progressive voters in the state who for whatever reason, didn't bother to show up at the polls. By not exercising your right to vote, congratulations, you helped pass this unjust amendment and through your inaction are now complicit in the oppression of other people.
You can blame the 61% of North Carolina's voters who for whatever reason, voted for the unjust amendment despite the best efforts of the large coalition that tried to 'ejumacate' people about what would happen if that happened. It is now regrettably part of North Carolina's constitution until either North Carolina's or the United States Supreme Court overturn it.