I don't think there is anything wrong with choosing to not immerse oneself in something one knows he or she would not enjoy. I like porn, but I don't watch male-on-male porn, because I do not find it appealing visually or emotionally.

Homophobia comes in when you have a fear, even a subconscious one, that subjecting oneself to (depictions of) homosexuality might somehow turn one gay. Extreme homophobes would take that to its logical extreme and say that it should be banned for the "good of society" or somesuch.

Anyway, just as not playing a game with a homosexual character doesn't make you a homophobe, playing a game with a homosexual character doesn't make you not a homophobe. It's basically indicative of nothing in and of itself.