If an objector hasn't the desire to perform the procedure under ethical or religious grounds, among others, they certainly should not be obligated to; the patient's rights do not supersede the potential doctor's as a standard, both are people, even if you consider the unborn to "not yet really be people". They are by objecting, quite literally, avoiding getting blood on their hands and instead opting to let someone else handle the touchy matter. Considering people somehow view butchery as a service to be provided, I think this practice of avoidance is a fair place to act on as at this rate the procedure of abortion I doubt to be going anywhere, so those against it should not be under any compulsion to perform it. 

If someone does take issue with that, then perhaps it should be their duty to likewise find a place that performs the service that does not have opposition to it. I am sure that would not be too terribly difficult, but you could name any number of cases where people have demanded someone provides them a service. To my memory, no one can be forced to provide a service generally.