Yes, it's bad leadership. IMO, good leadership is seeing what the individuals in your team are good and interested in, and adapt the work to that. Your 2nd para

Yes, it's bad leadership. IMO, good leadership is seeing what the individuals in your team are good and interested in, and adapt the work to that. Your 2nd paragraph describes the problem I'm highlighting. If for whatever reason someone is not interested in (or good at) mentoring, why expect them to mentor? Expectation from a leader cause people to feel forced to do them. People don't want to let their leaders down, but if they can't or don't like doing what they're expected to, they won't do a good job -- or the job at all. This obviously only applies to creative/knowledge work. I suppose it's less important in task-based/mechanical work.