Dermatologists, like feminists, are specialists in a field. They focus on one part of their field. In this case, medicine relating to skin, and social justice focused on women. This narrowed focus doesn’t make teir areas of expertise or focus invalid, or uncaring towards other related topics. In fact, generally it’s the opposite! Both groups in this example fall into both definitions: dermatologist AND doctor, feminist AND humanist/equalist). They aren’t mutually exclusive, they simply are specializations.