Historically marginalised and stigmatised, sex workers have a hard time in pushing for a reform of prostitution laws. Most politicians, especially if male and heterosexual, do not wish to be associated with sex work.
Prejudices and lack of knowledge about the topic as well as the unwillingness to engage with sex workers themselves have proven to be hard obstacles to surmount. Often, sex workers are heard in consultation processes, but their views and political claims aren't always taken seriously...
By contrast, anti-prostitution activists calling for a world without prostitution have been far more successful in their lobbying efforts against sex work. They also explicitly distance themselves from self-identified sex workers, who they often accuse of being nothing but criminals. Using the stigma of sex work, anti-prostitution activists have managed to ally themselves with mostly sexually and socially conservative groups in their call for the suppression of sex work.