Ya it is tough expressing the hatred sometimes. Once I beat up an Interista at a wedding and was heavily criticized for it. Once a Liverpool fan asked me to hold the elevator for him and as the door was shutting I responded "not in that jersey". The people in the elevator looked at me like I was the biggest prick in our building.
My point? You have to pick and choose where to communicate the hatred because society by and large doesn't get it. Being at work, the bosses would take the Intermerda's side. Just remember the face and bust his ribs another day.