Informal settlements toilets are unsanitary places, as are most public toilets. But the writer is confusing the consideration users ought to have for the next person, personal responsibility and pride and cleanliness with the fact there are no and can be no toilets in individual dwellings. Even in the home or workplace one gets annoyed when others who used the toilet, bathroom or any facility for that matter, before one has left it in a state. 
Axolile has reason for concern about sanitation in informal settlements as a general service, but his anger is misplaced, and self-pitying so, about the state of individual toilets. Have you surveyed whether users try and keep it as clean as possible? Or don't they care? Probably the latter (if one goes by the state of many public toilets).  Axolile, have you heard of the informal toilet cleaners of Nairobi's slums? If not I suggest you read up on them before complaining about city-provided toilets here.