Is it ok to harass someone

Who has been charged with domestic violence? A guy who drinks in the same pub as me was charged with that in May. Since then, when he's in the pub he gets pushed around, tripped etc, sometimes someone will move as if to punch him and he'll cower, which makes everyone laugh. He's been spat on too, he's claimed that if it continues he'll call the police, I don't think that we're doing anything wrong though