Yuck. I've been there. All I can say is, keep at it. I went to four doctors trying to get snipped (starting at age 23), and got the same treatment. Then, at my next physical, my regular doc saw all the urology consults in my file and asked what was up. When I told him, he put a nasty note in there about doctors minding their own business, and got me an appointment with the department head, who was very apologetic and did it himself.
So, I got lucky (except for the fact that it didn't take and I get to have it done again on Thursday -- yay!!). One tip I learned after the fact: after a doctor refuses to do it, ask his/her nurse if there's another doctor in the department who might be more open-minded. Also, I assume you're trying to find a doctor that's covered by an insurance plan, but if you're willing to pay out of pocket, Planned Parenthood should be able to hook you up without a problem.
Jeremy