I believe that the motivation of the Boy Scouts' policy is to protect the welfare of the boys who are members in a way that is consistent with their stated values.
You are beginning to sound like a real politician here.
The reason I question your sincerity on this issue is that you referred to "PC attacks" on the Boy Scouts for this policy. Whenever someone uses a phrase such as this, there is only one assumption that can be made - they feel the attacks are unfair and/or unwarranted. Calling something "Politically correct" is code for: "it's bull shit."
So I can only assume that you not only agree with the Scouts having a policy that is "consistent with their stated values," but also that you AGREE with those stated values, i.e., the Scouts SHOULD kick those little faggots out of the organization so that their "normal" boys won't have to be exposed to them.
No one will admit to bigotry, so I am not surprised at your reluctance to do so. That would be overt bigotry, and that is no longer socially acceptable. Today, we deal with covert bigotry which is supporting programs that make life more difficult for the targets of the bigotry, or which make it easier for bigots to take advantage of their targets.
I think the Scouts are imposing a policy of out and out bigotry if they expel gays from their organization. I will further say that anyone who supports such a program is also a bigot.