Y'know, it's really hard for a woman to tell a bunch of guys they're being sexist before they brush her off as an angry woman. It's really hard for a gay man to yell homophobia without people just writing him off as a noisy gay man. We all make really shitty advocates for ourselves.
What we can do, however, is make excellent advocates for each other. When a straight man says that gay marriage is a right, that means more than a dozen gay men saying this. When a gay white woman says that we should not persecute people just because they happen to be Muslim, it means more than a dozen Muslims saying exactly the same thing. When a Muslim argues that we must be more compassionate and respectful of our homeless, that goes farther than a dozen homeless activists.
We need each other, not simply as silent allies, but as vocal advocates, not just for unity--but for expedience. We do far more in the service of others than we would ever do for ourselves.