It's not about feelings though. It's about an act. It's hard to support one without the other, in this case. Those folks supporting the right to have an abortion, aren't supporting the right to believe in it. They're supporting the act.
You don't really have the right to hold any and all beliefs, when actions are accompanied with them though. Take honor killings for instance. You can't support the right to believe the most extreme form of Islam, while denouncing some of the acts that go with those beliefs.
"I support your right to believe in the religious merits of honor killings...just don't do it because it's wrong."