The "opposing fan coming in peace to just have intelligent football conversation" invariably devolves into a series of patronizing "no this is why you're wrong" lectures. For the life of me I don't understand why fans of other teams visit (or live on) an opponent's board. Never in my internet life have I ever had even the urge to post on another team's site. I would always lbe fine without opposing fans posting on this board - trolls, "intelligent football talkers", or otherwise.
It's like if you were at a Bills watch party with all hyped up Bills fans and there's one random guy with an opposing team jersey walking around fansplaining Yada Yada about his team. Even if you are cordial, read the room - no one wants you here