I think this issue has been addressed time and again on this and other left fora. No douby that Left has its share of puritanical characters who are uncomfortable about sex, but it would be gross oversimplification to reduce the whole issue to Puritanism.
As I see it, the problem goes well beyond sexuality and touches the following social-political issues:
1. Commodity fetishism - which is one of the main vehicles of capitalist colonization of everyday life;
2. The problem of nominally free will - i.e. justification of every form of exploitation as long as the victims nominally "consents" to it, while ignoring circumstances that leave him or her with little choice (that is particularly relevant to prostitution which many believe is a "forced choice")
3. Cultural imperialism and "one-dimensionalism," which creates a hegemonic corporate consumer culture at the expense of local cultures.
Again these are serious social-political problems that cannot be labeled "Puritanism."
Wojtek