I mean, there really is no big deal with it. People either care for it, which is appreciated by any involved faction, or they ignore it, either out of protest or for the sake of having simple fights. The treaty is merely a regulation to ensure people know when they get shot by someone that usually wouldn't shoot them. In that case, it's their fault and they have to live with it. Since it is currently mostly only enforced by LH and Rogues, it's not even that much of a hassle.
People getting angry over it are just looking for a reason to express anger.