I remember first encountering this behavior at Stanford in the early ‘90s. People would walk over and join a conversation, say they were offended by something, and then stare back at you, expecting something. Perhaps naïvely, I didn’t understand why anyone would care that another person was offended, so the behavior puzzled me. They would then go over to another conversation and do the same thing. They would often receive apologies, which appeared to be the outcome they desired. But these people seldomly added anything to conversations or the community, so over time I learned to avoid them.