I don't think there's any intrinsic objection to digging up human bones, but there should certainly be considerations of the feelings of others related to the decedents.
Now, if they're arguing that their recently deceased Aunt Minnie's grave should block off digging up fossils that might illuminate hominid descent, well, dig ole Aunt Minnie up, and give her a dignified reburial, and get on with the excavating.
Now, if they're arguing that their recently deceased Aunt Minnie's grave should block off digging up fossils that might illuminate hominid descent, well, dig ole Aunt Minnie up, and give her a dignified reburial, and get on with the excavating.