Lori Hahn (of Hahn at Home fame) has an interview with retired Lieutenant General Claudia Kennedy that is definitely worth a read. Hahn, a former military member, served with Kennedy earlier in Kennedy's stellar career. Kennedy retired from her last position as Army Deputy Chief of Staff for Intelligence - at that point she was the highest ranking woman ever in the US Army.
The interview is a fascinating glimpse into Kennedy's career and her thoughts on Don't Ask, Don't Tell - including a story about her discharge of a Chinese linguist under the anti-gay policy. A sample of the insights Kennedy shares:
I think it's easier to deal with race and gender than sexual orientation. Because someone who wants to advocate for a minority race sitting as a member of the majority race can still kind of keep their life clear - they're white advocating for (a minority). So they don't have to deal with being brushed with the stigma of race while advocating for another race.
Same with gender. Nobody thinks this man who is a feminist is now going to become a woman, so he doesn't have to be brushed with the stigma of being a woman.
So, then when you take a look at sexual orientation, when a member of a majority group of heterosexuals advocates for homosexuals, they need to be willing to be brushed with the, "Maybe you're a homosexual" stigma. I think that's much harder to do.