It has been my experience that everyone is in complete control of his/her own destiny - except when he/she isn't. Let's be real, shall we. In an ideal world what you say would be true. But the world is far from ideal. People make mistakes. People get down. And, of course, experienced people use inexperienced people before the inexperienced people realize what is going on.
I'm not suggesting we ban the pill. All I'm saying is that it is wrong to dis-associate conception from sexual behavior. And I'm also saying that the primary beneficiaries of such a dis-association are the men. The entire sexual dynamic changes when it's possible that the woman could get pregnant. And the normative case is for a woman to be far more interested in sex as part of an intimate, permanent relationship and the man to be far more interested in sex as a fun game with no long-term implications. Societies are more stable when the former approach is encouraged and the latter is discouraged.
As for the advent of the Pill, there are those of us out there who may need and use this for medical purposes. There are certain imbalances and conditions that can be controlled with the pill. Not every single woman who is out there and taking the pill is a promiscuous heathen.
Not even every single woman who is using The Pill for birth control reasons alone is a promiscuous heathen. But then, not every person using The Pill is a saint, either. There's no question that hormonal regulation can be a good thing. But every good thing can be abused. We should have established a better understanding of sex and sexuality before developing The Pill. The Pope tried to warn us. But, as has been the case since the beginning of man, we never want to listen to G-d's advice when the alternative seems more fun.
Shalom.