Explain and illustrate this reference...?

[Hayley]

Social justice...is neither the exclusive terrain of social welfare nor of crime control. indeed, the boundaries between these two domains tend to be mobile and porous.
any help with this reference would be great. Thank you.

[Maestro]

This gets to the hard and soft side of social justice. Do people do bad things because of their circumstances or because they are bad people? The real answer is yes and yes. Bad circumstances, such as poverty, encourage more people to take drastic measures. Abused children or children who lack a father figure have a harder time growing up to be "decent", but it is not necessarily true that they won´t. Some people who had all the advantages in life as they were growing up also turn out to be bad people. There´s just something wrong with them morally, emotionally, and mentally.

Your quote tells anyone considering what social justice is to not go to either extreme: excusing bad behavior by blaming it on a person´s sordid past nor going to the other extreme and being unmerciful and relying solely on strong punishment.

[Froggy]

'Social justice...is neither the exclusive terrain of social welfare nor of crime control.'

'Social ....' - has no relevance to social 'welfare' (well-being - prosperity - weal - good).

'...... justice' - has no relevance to crime 'control' (govern - check - manage - direct - rule - supervise).

'Social justice' is a term coined by politicians and the media to appease the masses and to make people believe that what is done in the way of crime sentencing is in their best interests, but is often to the detriment of the victim rather than as a deterrent or punishment for the perpetrator.

The term is therefore 'movable' (mobile) to suit the situation and so full of holes (porous) in it's application, that even the laws themselves can easily be circumvented.