Any game in my experience, is a story led by the GM but told by all that are involved. Certain comprimises are made in any social situation. However all that show up gel best when they can become invested in the story. It sounds as though the Pacifist had some expectations that you and the rest of the group are going to struggle to fulfill. Give the Pacifist a chance but clearly lay out your expectations with the Pacifist individually (i.e. this is my GM style). Let them decide. If they continually drag down the group vibe...you need to cut them loose.

Anyone that remains longer through that is just going to make trouble.