"There has to be an easy mechanism"....     

There's nothing "easy" about it, nor should it be easy for a Govt to revoke citizenship.    If you take your emotion out of the equation and think practically - how would this be done?    For a single citizenship Canadian - where and what country does he go if citizenship is revoked?    Does he become a refugee somewhere - do we simply export the problem?    If you're just talking about dual citizens - then that would mean they face a different set of laws for the same crime a single citizenship Canadian might commit.    

The problem with "easy" is that it's populist.   The "easy" thing to do is go with the mob or majority.    NO Govt should have the power to simply do what's popular (despite our laws).      And why any thinking Canadian would want to grant a Govt (ANY Govt) this type of power is beyond me.     Laws are meant to protect citizens, whether you like them or not.    This means protection from the Govt too.