I wouldn't use the word "retarded," because I think it brings improper connotations.
However, suggesting that $5 per day is exploitation seems as though it would be based exclusively on the ethnocentric view from someone in a land where $5 a day is paltry.
In the United States, where I live, even $5 per HOUR would be illegal, but the reason the minimum wage is what it is is because of cost of living. A large pizza and drink can cost more than $20 in the United States. A cheap house is $90,000. A cheap college education is $20,000. A used car is $7,000. A movie ticket is $15.
That's not the case everywhere else. Where cost of living is lower, minimum wage tends to be lower.
It reminds me of the move EuroTrip. These kids find themselves in a small, Eastern European country with very little money, by their standards. However, they soon realize that the little money they have is lavish wealth where they are.
Now, the movie definitely takes this exchange difference to extremes, but the point is valid. $5 to an American is not much. Maybe it can buy you a lunch.
In a country where $.70 can buy a lunch, $5 is far more valuable, because it will go further toward paying for things there.
All that to say, in a land where minimum wage comes out to about $2.50 per day, $5 is not exploitation.