A lot of players just don't understand how the games work, especially if they casual bg. Maybe an overview on the bg loading screen would be useful or an optional pop up frame during preparation time. Once players understand things like why not to cap certain nodes or why hold a flag or why (and where to) grab bombs, they usually enjoy the bg more and participate better. Some people will always grief and some will always be more interested in hk farming, and that's fine but there's still a lot of people willing to learn and cooperate.