Beneatha brings people over to her home, even though she thinks the family is ignorant, for several reasons. First, having a young man call for a young woman at her home was standard for this period of time. If the two people skipped this somewhat expected custom, it might be considered poor manners or a breach of proper etiquette. Second, it was probably easier for Beneatha to bring people over because exclusively having Joseph Asagai or her other college boyfriend entertain her outside her home could get very expensive and translate into seeing one another less frequently because of the cost of the date. Moreover, even if Beneatha thinks her family is ignorant, as many college age students believe about their facilities, she still loves them. She loves Mama and her nephew and despite any sibling issues her and Walter might have with one another, they still love one another.
This also might be another reason why Beneatha would bring people over to her home so that she can model certain behavior for her family and instruct or at least enlighten them about things she is discovering during her education and her relationships with new people and help them discover new ideas for themselves. Her relationship with Joseph Asagai, who is from Nigeria, opens her eyes to her lineage and she wants her family to understand how she now embraces her heritage. She had accepted American culture as her own but begins to question this. She begins to play African music at home and to wear African attire in an effort to understand more about the culture. She seems to want to share some of these new thoughts with her family in an effort to open their eyes, just as she believes her eyes have been opened for the first time.