For example. There are a lot of people that claim verbal aggression does no exist, there is no such a thing as a verbal aggression, it must be physical to be an aggression.

Ok, then what about a threat? The announce of aggression. If one answered it with "preventive" violence, was it aggression or just responding a threat ?

Then you hide your threat in a symbol that not everyone would recognize immediately as a threat, and then go showing off. Flags ?

If my neighbour has a nazi flag and I want it removed, who is the aggressor ? Does the answer change if I set fire to it ?