What is Inclusivity?

I discovered today that being an inclusive church means that we perform "same-sex marriages ". If we don't, then we don't believe that "God so loved the world...." Apparently we believe that God didn't send Jesus to die for people that the Bible describes as sinners; instead, we believe that Jesus only died for traditionalists. I'm confused, naturally. If God so loved the world so that all who believe in Jesus will not perish, then surely there must be a danger that some people will perish and not have eternal life. Calling sin sin doesn't mean we are not inclusive, or that we hate people. Surely it means that God loves everyone. Shouldn't that mean that we are inclusive? Haven't we always been inclusive? Isn't that what "The 4 Alls" are all about:

All need to be saved

All can be saved

All can know they are saved

All can be saved to the uttermost

Sounds inclusive to me. But maybe I'm wrong!