Inevitably cynical political take, based purely on a distant view:
Although there are plenty of liberal chapters in some areas, the BSA overall is controlled by the right.
They had been making extremely belated and grudging concessions to modernity in recent times, in response to declining membership. However, the rise of the Trumpists has now seen them reaffirm their allegiance to the right, as demonstrated by their tolerance of Trump’s adventures at the jamboree.
But their membership is declining faster than ever, as more and more left wing parents withdraw. And, at the same time, right wing parents are rejecting the Girl Scouts as insufficiently bigoted.
So the right wing BSA leadership want to shore up their membership, and they also want a right-wing alternative for girls. Hence, the current news.