When I first began Diversity and Inclusion work in organizations over 20 years ago, there were those in the D&I community who did not think that LGBT people had a seat at the Diversity table.
Race and gender and other dimensions of diversity had a seat, but if you were a Black lesbian, a Jewish gay man, or a Latino transgender woman who was blind, there was a line in your level of inclusion.
We didn’t want to be left out, not hired, or disrespected so we left a crucial part of ourselves out. Those who were brave like Brian McNaught, and Roslyn Taylor O’Neale paved the way and opened the gates for the rest of us. Although is was scary at times, the more people who came out, and let their neighbors, families and co-workers know them as whole people continued to make it easier for others. We knew that to “play it safe,” wasn’t safe and that our safety and acceptance was in building relationships with people who were not LGBT. 
I believe those interpersonal relationships made the difference, and helped create the groundswell of support for same-sex marriage. For the most part, people who liked their co-workers on Saturday still liked them when they found out on Monday that their co-workers were LGBT.
I often get asked to speak to organizations about LGBT inclusion.  Twenty years ago, one man told me that I couldn’t use the word “gay” in the workshop because he had a friend whose name was “Gay.”  Another man told the group that his brother who had been in the Marines was gay. “I love my brother, he said, and I’ll use the word “gay” any time I want.  At the time, the second man was an anomaly. I’m no longer surprised to see “straight allies,” defending the rights of LGBT people.
When I wrote about my personal experience regarding the death of my partner and the need for same-sex marriage, I received letters and calls from all over the world.  http://www.cnn.com/2013/05/01/opinion/lieberman-same-sex-marriage/
There is still work to be done to win hearts and minds of people who are ignorant, biased, and afraid. We have to continue to work to stop homophobia and transphobia and to continue to build inclusion at every level.
Today, LGBT people have a seat at the table today, and we can bring our whole selves to the conversation.  Otis Redding said, “A Change is Gonna’ Come,” Bob Dylan said, “The Times They are A Changing,” and the Supreme Court said, “Change happened in June 2015.”