Even some gays are against same-sex marriage. And that does not mean that they are also homophobes.
A position against SSM does not imply homophobia because it is not necessarily based on hatred or aversion towards homosexuals. For instance, there is no justification in calling Eich a homophobe.
What bothers me is a tendency of LGBT activists to put a homophobe label on everyone with an opinion they do not like. That is a witch hunt.