Because they are SO FUCKING STOOOPID!!!
Update: Mike Huckabee provides even more evidence for the Stooopid thesis (my emphasis):
“[I]t’s tragic that the Planned Parenthood organization now tries to present themselves primarily a health organization when they are primarily an abortion provider…. They provide some services. I will grant you that. But they are maybe on the fringes — are external portion of what they are primarily all about.”
Wingnut math: 3% == “a primary service”.