There are surely plenty of reasons, but the one that gets little attention is class.

It’s obvious but still bears underlining: When every economic and social class shares in the experience of injustice or intolerable wrongs, things change faster. If only poor people were gay, does anyone think our political leaders would have “evolved” at this pace? Likewise, if we had a draft, does anyone think our wars in Iraq and Afghanistan would have proceeded as they did?

Today we all have friends, colleagues and relatives who are gay. That’s the way societies change. The moral circle widens. The boundaries of empathy expand. This was the genius of the strategy in Harvey Milk’s passionate refrain on Gay Freedom Day almost 35 years ago: “Come out . . . come out . . . come out.” Despite the pain and risk, Milk knew that once enough gay men and women found the courage to stand up, it would became impossible to sustain bigotry or defend discrimination.