Why Is CP Illegal?

Until the late 70's you could buy CP over the counter in California, and probably other places. WTF happened? If it was OK then, why is it not OK now?

Semantic faggotry aside, it's a somewhat interesting subject. How exactly did we go from CP being a strange but acceptable fetish to it being, according to mainstream culture, a great evil?

It's not just the mainstream, either. Ask anyone, even the most liberal hippy in the country, and he'll tell you that he accepts everybody, every single person, except for racists and pedophiles. Those two groups are special to the point that mousy, gentle girls exclaim that they should be tortured to death. So how did we get from there to here, anyways?