It sounds like F. Wesley Schneider was a pretty big driver of that for Paizo. The forum posts on the Paizo forum from him announcing his departure had a few people referring to what a huge advocate he was for including that material.As far as representation Paizo was pretty big on putting in prominent LGBTQ NPCs (both good and bad) in their 3.5 and Pathfinder adventure paths (and eventually their iconics) and making romantic NPC options explicitly pretty open for groups. Also they made steps since early on as a company to be openly and actively welcoming to LGBTQ gamers specifically.
Green Ronin was earlier with the niche romance fantasy RPG Blue Rose, but Paizo was a much more prominent and mainstream RPG publisher with a broad reach and impact for representation.