Apart from small disputes,the HA and the mafia always respected each others territory.
When the bikers in Montreal had their wars in the 90's. Although Vito leaned more with HA,they chose the role of mediator between HA and the Rock Machine.They could of moved in and seek more control but chose not to. Now we are supposed to believe that HA are now in control and no questions asked. I am suspicious that there is something else going on here. Why would HA risk a possible war in the future with the mafia. All it takes is a few police raids on the HA to unbalance the scale and a war can break out again. Unless the Mafia or the Mafia dissidents decided to make an alliance with HA. If this is not the case then I find it remarkable that the HA were able to takeover without losing one MC member. It is too hard to believe.