He just kill all people who are involved in drug. You don't solve problems just to murder all who don't fit you ideally country in his eyes. A country without drugs don't exist it will always be part of the world.
Yes that's true, you don't need to kill those who are proven using drugs, you have to rehabilitate them. But in the Philippines, they kill all the users, even those who are innocent and not involve are blamed. They can only kill the members, but can't even find the master mind of all this drug problem. Its because the main problem and the master mind of all that problem is in the government too, working and serving the country but in the other hand destroying it.