From the article:
When she first got wind of the change, the Girl Scouts’ board president emailed the entire BSA board saying the decision would be “fundamentally undercutting Girl Scouts of the USA.”
That's business. Why are you expecting another company not to compete with you? The idea of demanding that another organization not step on your market share is laughable.
It's my understanding that the GSA argument is something like "young women do not feel comfortable assuming leadership roles around young men, and young men dominate such inter-gender situations. Young women learn leadership through GSA and flourish. Therefore, GSA is important and necessary to continued American world domination."