I do not know why did they?
They go to public school together. Some girls maybe take shop, some boys may take home ec. they play in the band together plus other school activities.

Gives them the chance to interact together outside school. These are boy scouts, not cub scouts.

Women engage in men's occupations and men engage in women's occupations. All falls back on peacefully interacting together.

Women join the military now.

Girls joining boy scouts may cut down on male dominance of females. Boys are taught that macho sh!t at an early age.

I just saw two boyscouts this morning. I think the appropriate question is why didn't they.

I'm shocked Trump had nothing to say about this controversy. Maybe it's because he was never one.