My friend on Facebook posted an intriguing question the other day. She asked why straight people who support gay rights feel the need to emphasize their heterosexuality. In her view, it's an attempt by that person to avoid being judged by critics as one of "them," and diminishes said support.
Here's the answer I gave her:
I do it because I know that it's an absolutely foreign concept to many people that someone can support anything outside their direct self-interest. Not just for LGBTQ rights, but for anything at all.
When I say that I'm not gay but support gay rights, that I support marijuana legalization even though I've never used it or that I like Jesus' teachings even though religion appalls me, I do so to shatter those people's notions of self-interest — and I do it out of allegiance, not disgust. Whereas before those people might have thought that only LGBTQ people support the cause, they realize that isn't the case, and maybe they can support it too. It's an uphill climb, but in my experience, it works.
I know from experience that people often repress their views because they think only certain people (who they aren't) can hold them. This isn't limited to gay rights — I met people in college who truly, genuinely thought that any progressive ideas were the exclusive province of long-haired, anti-American, hippie activist stereotypes. When they saw that I was a clean-cut, friendly person, it shattered that notion for them. (Just like others dispelled some of my own notions in the past.) I'll never forget someone blurting, "You're so normal for a liberal!" It didn't necessarily change their mind about anything, but it challenged them at least for a split-second. Sometimes that's all you can ask for.
Keep in mind, I never set out to do this, and it's a shame that it's even possible in this day and age. But it goes to show how deep perceptions can be in people, and why it's important sometimes to highlight that contrast. Far from being a divider, it can be a strong unifier, often in the most unexpected ways.