Excellent points, I think Penny has been very lazy with this piece and as SGM says up thread it seems have been motivated by spite towards Rad fems.
I have dug up these two pieces, one by Fin Mackay and one on Laurie's Blog.
pennyred.blogspot.co.uk/2010/03/sex-work-shibboleth.html
finnmackay.wordpress.com/articles/prostitution-is-violence-against-women-labour-left-review-nov-07/
Both are worth a read, Penny in her blog specifically mentions Fin Mackay,
Penny says "Feminists need to put aside ideological differences and work towards a radical restructuring of neoliberal attitudes to sex, to work and to sex work" but it would seem that SHE has fallen into the trap of creating divisions.
She goes on to conclude that "If we want a world where women?s bodies are more than just commodities, feminists need to get radical, we need to get smart, and we need to be prepared to lay down our weapons and take the fight to the real enemies. If we stop fighting each other and turn our energies on the pimps, the abusers and the superstructure of misogynist free-market capitalism, there are exhilarating victories to be won"
So, in the final analysis, both want change under capitalism, both would agree that abolition of capitalism is either the way to achieve change or part of the change that is necessary to free women.
If Laurie really believes that it is time to put aside ideological differences, it might be better to find some way of synthesising Marxist and (patriarchy)radical theory rather than attacking rad fems as prudes.
What is really needed is a new theoretical framework that takes account of both the economic (historical materialist) and the humanist perspectives (radical feminist) and makes sense of women's oppression under one theory. Perhaps she could apply her planet sized brain to that 