Once upon a time, women were treated as sub-humans, not protected by the same laws as men, and ill-treated without consequence. That time is gone for the most part.
Once upon a time, slaves were kept, treated as sub-humans, not protected by the same laws as non-slaves, and ill-treated without consequence. That time is gone for the most part.
Once upon a time... blacks...
Once upon a time... homosexuals.
How can anyone not see the correlation?
The shifting moral zeitgeist is slowly and painstakingly overcoming the prejudice and ignorance that led to these various groups being denied the same rights and priveleges of others.
Hopefully, some day, a person's sexual inclination will be of as little importance to the state as their eye colour. That day is long overdue.