We have to realise Marawi City has a 99+% population of Muslims, so again its in there own Backyard that people are causing unrest, as for it being Martial law in the whole of Mindanao surely its easier to police when it covers the whole of Mindanao, rather than just a small section such as Marawi city, we are all aware this is not the only city on Mindanao thats predominantly Muslim, and we know what there aims are..
As for bringing in Martial Law, what else is Duterte supposed to do, the alternative is to let them get on with it, thats been happening far too long, and we see the results of that Worldwide..