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.
Supporting traditional marriage is NOT bigotry, I am a supporter of traditional marriage, I dislike but respect other people's version marriage, But that does not make me a bigot. Not supporting same-sex marriage is for some wrong but it's an opinion and thought that is protected by free speech. So it is not bigotry.