The treatment and status of prostitutes seems to have been driven less by a sense of justice as an abstract concept than by a commitment to maintaining the social order. In the middle ages it was believed that the social order was best served by providing a safe outlet for male sexual desires that could otherwise potentially be released in a more disruptive fashion, but then there was a shift to a belief in more rigid control and enforced purity. The basic goal (preventing 'respectable' women from being corrupted) remained the same, but there was a new perception of sin as a contagious disease hat needed to be cut out entirely rather than merely kept within reasonable limits. The belief in collective salvation seems very much on display, as the sins of the prostitutes represented a threat to the entire community. The obsession with procurers is consistent with this, as they were seen as an active corrupting influence.
I think it's interesting that the courts attempted to enforce an elite model of family and gender roles on lower class families, when the reality of daily life in fact utterly precluded any possibility of them meeting those standards. This is another example of attempting to enforce the social order.
And of course it's important to note the different treatment of men and women. Women seem to have been considered more inherently sinful, and thus subjected to more thorough interrogation and were punished far more severely. Roper notes that even when men were investigated and punished, it was often conducted in private rather than as a public spectacle.
