The business about the Boy Scouts not allowing gays in is part of a larger picture of exclusion and bullying. We human beings have a strong prejudice against anyone who is "different."
When I was in kindergarten, I walked from our home to the old Douglas School on 1300 East. I was not homosexual, but I was different. I was born with a cleft lip and palate. My front teeth were crooked or missing. A group of boys would call "Eee-ahh, eee-ahh" as I passed them.
There is a deep instinct to weed out the different members of the herd. That is why some want to exclude gays.