There is way u can be a peacful faction that can't be attack
Like it was said, the peaceful factions can easily be abused. Let me enlighten us all with a scenario.
Faction A (for applesauce) is at war with Faction B (for Banana)
Faction D (for Dingleberry) is a peaceful faction, but the leader (Dingledork123) is friends with Faction B's leader (Bananasplitandrun) So, because Dingledork's men can wander the world and take no damage, Faction B asks if Dingledork and his troops can walk over to Faction A, inspect the land, get a layout of it, and report everything to Faction B. Faction A is unable to stop them, as they cannot kill them.
Was that not good enough for you? Heres another scenario.
Faction A has discovered a huge vein of diamonds, but they don't have a pick with them so they post 2 soldiers to defend it while a third leaves to get a pick. Trollipopper567, a member of a peaceful faction, sees them defending the vein, and begins to mine it. Faction A is unable to do anything to protect their amazing find, as Trollipopper is invincible.
In short, I don't think that peaceful factions should ever be implemented, especially in a server like this where there is more to warfare then raids. And with peaceful factions out of the question, there is no feasible way for me and my fellow faction members to retain our cherished homeland when we are attacked and killed by a bunch of anti-RP hardcore raiders.
I rest my case.
((all of those names were made up, I am not trying to insult any non-existant players))