bone of contention means ... why is it special like why is Jerusalem a bone of contention to Judaism ....this means why is Jerusalem special to Judaism.
"He doesn't have a ____ bone in his body" is a way to state something about another person with strong emphasis. For example:
"He doesn't have a mean bone in his body" would obviously mean that not...
The expression, "A bone to pick with (you, him, her...)," is an idiom. It has absolutely nothing to do with bones. It means the person does not like something you are saying or doing and would like...