1. because of the reasoning behind it.
There are far too many organizations in the US that feel that they have the right to force their morals upon everyone else. As is happening so frequently with any organization that has even a miniscule relationship with Planned Parenthood, they get targeted by groups who want to regulate your sexual activities and "make you pay" for not doing "it their way". By having sex "your way" and getting counseling from Planned Parenthood for undesirable and unplanned consequences later, you're violating the "rules" as designated by these "morality police". [link|http://www.austinchronicle.com/issues/dispatch/2003-12-05/pols_feature.html|Go here to read about how harassment and boycotts have targeted the construction crews building an Austin, TX Planned Parenthood" facility].
2. because it hurts the individuals and the local troops.
The girls sell cookies to pay for activites that their troops undertake, such as sleepovers at amusement parks. The girls themselves receive credits that they can use to reduce the costs of going to Girl Scout camps while additionally qualifying for honors (ribbons, plaques, medals, awards ceremonies) that go to high selling Scouts.