This is a very important question. The indigenous communities are doing invaluable work. They are essentially risking their lives to fight drug trafficking, to fight armed cartels and make sure that they are not operating in their territories. That's exactly the reason they are being killed.
Their leadership is fundamental for Colombia. These indigenous and Afro-Colombian leaders play the role that state authorities should be playing in their rural and remote communities. Without them, most people would have nowhere to turn when they have their rights violated or they would have nowhere to turn for protection.
Their role in these communities is indispensable. They are attacked precisely because they are doing this job. That is the reason that international pressure is needed on the Colombian government: to make sure that these indigenous and Afro-Colombian leaders are being protected.