By the strict sense of this question, no, of course not, because very few people will actually argue against traditional marriage and that it should be banned. However, I assume that the author meant "Is it bigotry to be against same-sex marriage?" and the answer is yes, if you try to stop others from doing it. If you don't like gay marriage, don't get gay married. If you try to stop others from doing it because you personally disagree, you are a bigot because you cannot tolerate other people.