A little imagination

Imagine that you live in a beautiful mansion with an enormous garden in the back.  To the south of your mansion are a series of tenement slums.   You are now worried that the residents of those slums will break into your garden and steal the fruit from the trees.  Some residents may  become squatters in your garden or even in your house.  You have two options:  One, you could build a fence, hire security guards to protect the perimeter, and hire some more guards to find the squatters and throw them off your property.  The second option would be to improve the lot of those living in the tenements so that they will be content to stay in their own homes.  The second way is better because it is cheaper, safer, and more ethical.