Long ago, all the way back to last January, Lady Saika wrote a post about Homophobia and Slash Fanfiction. At one point she discussed why people have a difficulty imagining some of their favorite characters as a sexuality other than straight. She wrote:
Part of this is rooted in persistent and terrible stereotypes. If, when you think ‘gay’, you think ‘faaaabulous’, you’d never imagine Dean Winchester getting into a relationship with a guy. If when you think bi, you think ‘slut’, you never would imagine someone like Durarara‘s Mikado as bi. If you think ‘butch’ when you hear ‘lesbian’, you’d never in a million years think of, say, Luna Lovegood as a lesbian.
The same is true in the reverse. If a woman doesn’t want to get married, is into sports, is a warrior, is basically not stereotypically feminine, then automatically people assume that woman is a lesbian. Now don’t get me wrong, these characters could very well be lesbians, bisexuals, pansexuals, asexuals, straight, or whatever; my problem is assuming someone is homosexual based on gender stereotypes.