Why would he necessarily think those who have tried to contact him are people? He could think only he and his tribe are people and the others are: 1. aliens 2.

Why would he necessarily think those who have tried to contact him are people? He could think only he and his tribe are people and the others are: 1. aliens 2. demons 3. spirits 4. some animal 5. lesser humans 6. and so on Numbers 2,3 and 5 are not too far fetched. Heck even in the 20th and 21st century there are modern cultures that think this way. Racism is really all about #5. Various fundamentalist religions have a tendency to think in terms of demons and spirits. It is a completely valid hypothesis that he believes he is the last man on earth or the last 'real man' or whatever.