It's not an excellent point. The poster doesn't know - BSA has a charter giving it sole use of the word "scout". And THAT'S why you don't see "Queer Scouts" or "Transgendered Scouts" etc.
P.S. (I wouldn't want to see that happen, either. But I do think BSA should be either required to admit the nonreligious, as it already admits every other type of religious belief known to man, including that of the people who murdered thousands on 9/11, or not permitted access to public school students during school hours, as it is in my town).
"BSA has a charter giving it sole use of the word "scout"."
Charters don't make for such protections, trademarks, tradename, and copyrights do, but the word "Scout", alone, would be a weak registration and most likely not hold up. If someone wanted to use the name "Queer Scout" they would be free to do so.