And it provides the same result as "don't ask; don't tell": it creates an environment where people are not free to be honest about who they are and sets up a structure that reinforces the idea that one kind of person is inherently better than another. The BSA also does this to boys at an especially formative time in their lives.

Why is scrutinizing the leaders any more acceptable than scrutinizing the boys?

The world is a heterosexual mens' club. The rest of us would like to be included.

I defer to your experiences; only consider Boy Scouts is no different from gym class, the mall or any other place boys congregate.

Also we separate the boys from the girls at this age, because it's helpful (reduces acting out, focuses goals). That's not considered a terrible thing, at least by youth leaders who have a dozen young people to teach/train.

Especially coming from my experiences as a camp counselor, I totally understand the value of separating boys and girls sometimes. I can't think of any circumstance when it would be useful to separate a group of adolescents by sexual orientation, but I won't say such a circumstance doesn't exist.

The problem is, unlike gender (currently disregarding transgender/gender queer/intersexed folks), you can't determine someone's sexual orientation - especially at this age. So it's not so much that the world is a heterosexual mens' club, but more that the heterosexual men think it is. As a result, they speak and behave based on that assumption. This assumption further marginalizes those who may already feel like outsiders within their own community.