Multiple reasons
1. The Girl scouts does not have the same activities available.
2. Boy scouts has more troops and meeting time place options. (For instance, when my son was in cub scouts my daughter participated and was very interested. We looked into girl scouts, but the nearest troop was a city over and only held meetings on days when we, me and my husband, both worked, so it was a no go).
3. Boy scouts already have girls (siblings, cousins, ect.) participating. The major change will be that girls will now recieve recognition for their participation, pay membership costs, and buy uniforms and other equipment from the boy scouts (it's about money).
4. What part of "separate is inherently unequal" is hard to grasp?
6. There was no need for the boy scouts to change their name, but whatever.
5. Girl scouts should also accept boy members.