I'm not sure what kind of feminists you're coming in contact with or referring to, because most feminists I know are very pro-birth control. Hell, I think in almost every single women's studies course I've taken, we've had long, drawn-out discussions about birth control and how sex ed needs to be taught in schools and how teens need to be educated about birth control and places like Planned Parenthood where you can go get free birth control (OMG free condoms~!). *shrug* But those are just the feminists I know. I'm sure there is some radical feminist subgroup out there that believes they shouldn't have to use contraception.
I'm refering to a very small minority. And come to think of it, my argument wasn't well thought out. My apologies.